- I don't know why, but there's something I don't like about that woman.
In this sentence, is "why" a noun? If not, what is it?
The word "why" in your example is most likely an interrogative word.
RATIONALE:
The matrix verb "know" can take an interrogative clause as complement. And the complement "Why" in the OP's example seems to be an interrogative word of a truncated interrogative clause. For example, let's use the following sentence(s) to show this:
- Tom doesn't like that woman [because that woman had kicked his dog]. -- (declarative clause)
That above sentence has the form of a declarative main clause; and the reason why Tom doesn't like that woman is "because that woman had kicked his dog". We can convert that above sentence into a corresponding interrogative main clause with the interrogative word "why" in situ:
- Tom doesn't like that woman [why]? -- (interrogative word in situ)
Note that the interrogative word "why" corresponds to the reason "because that woman had kicked his dog".
We can front that interrogative word "why", which causes subject-auxiliary inversion when the interrogative clause is a main clause, and produce:
- Why doesn't Tom like that woman? -- (interrogative word fronted, subject-aux inversion)
Obvious stuff, so far.
Now, let's have a person A talk to a person B to find out why Tom doesn't like that woman:
We can paraphrase the B1 response as: I don't know the answer to the question 'Why doesn't Tom like that woman?'
(Aside: Notice that the B1's subordinate interrogative clause "why Tom doesn't like that woman" doesn't have subject-auxiliary inversion that was seen in the corresponding main clause.)
Person B could have responded slightly differently, but with the same meaning:
or even as,
We can paraphrase the B2 and B3 responses as: I don't know the answer to the question 'Why doesn't he?' and I don't know the answer to the question 'Why?', respectively. We know that the embedded questions in B2 and B3 are shortened forms of the question "Why doesn't Tom like that woman?"
Thus, the "why" in the OP's original example could be considered to be an interrogative word. That is, the word "why" represents a shortened form of an embedded question somewhat similar to "Why don't I like that woman?"
-
- I don't know [why], but there's something I don't like about that woman. -- (OP's original example)
-
- I don't know [why I don't like that woman],
but there's something I don't like about that woman.
where #2 could be paraphrase as: I don't know the answer to the question 'Why don't I like that woman?'
Notice that if the shortened form is replaced with the longer interrogative clause (as is done in #2), then there is a duplication of the string "I don't like (about) that woman" in the sentence in such a way that the result is awkward and unwieldy, and the result might even be ungrammatical (which is why the last half of #2 was struck-through). This could be a reason why, in #1 (the OP's original example), the interrogative clause was truncated to merely the word "why".
RATIONALE: Why the word "why" in the OP's example is probably not a noun.
The dictionary on my iMac, New Oxford American Dictionary, has this as the "noun" part of the definition of the word "why":
noun ( pl. whys )
a reason or explanation: the whys and wherefores of these procedures need to be explained to students.
That sounds somewhat reasonable (that is, for our purposes it might be good enough). In that dictionary's example, you can see that:
The noun "why" inflects for number: singular "why" vs plural "whys". And you can see that their example uses the determiner "the" in their noun phrase (NP), e.g. "the whys of these procedures". In general, a word like the article "the" will usually only be found in an NP (though there are exceptions).
Also, notice that in the expression "the whys of these procedures" that the head noun "whys" has a dependent of-phrase "of these procedures". An of-phrase is often found as a post-head dependent in NPs.
Now let's look at the OP's original example:
-
- I don't know [why], but there's something I don't like about that woman. -- (OP's original example)
I would consider the word "why" to be a noun if it had been in something like:
- "I don't know [the why of it]".
where the NP "the why of it" would have a determiner "the" and a post-head dependent of-phrase. But the OP's original example doesn't have its word "why" in a phrase that has a structure that is commonly used by noun phrases. And the interrogative word rationale appears to be much more convincing, syntactically and semantically.
RATIONALE: Why the word "why" in the OP's example is probably not a relative word.
The dictionary on my iMac, New Oxford American Dictionary, has this as the "relative adverb" part of the definition of the word "why":
relative adverb
(with reference to a reason) on account of which; for which: the reason why flu shots need repeating every year is that the virus changes.
• the reason for which: each has faced similar hardships, and perhaps that is why they are friends.
The first part of its definition appears okay, as it corresponds to what is in the 2002 CGEL. The dictionary's example has an integrated relative clause and its antecedent:
- The reason(i) [ why(i) flu shots need repeating every year __(i) ] is that the virus changes.
The relative clause is:
- "why(i) flu shots need repeating every year __(i)"
Notice how the gap inside the relative is co-indexed with the relative word "why" and with the antecedent "reason" (which is a noun). This is all unremarkable, as this is typical for an integrated relative clause.
Notice how in this example that the noun "reason" is a variable that has the value "that the virus changes", and so, the relative clause can be seen as corresponding to something like the following main clause:
- "Flu shots need repeating every year [because the virus changes]." -- (main clause corresponding to the relative clause)
To create that above main clause, the gap in the relative clause had been replace with the previously missing reason.
Here's some related info in CGEL as to this relative word "why". On page 1051:
Why
Relative why is used in a very narrow range of constructions -- integrated relatives with reason as antecedent:
[54]
i. That's the main reason(i) [ why(i) they won't help us ].
ii. There was no reason(i) [ why(i) he should stay at the dance any longer ].
iii. I can't see any reason(i) [ why(i) you shouldn't have a little fun ].
The majority of examples are of the types shown in [ i-ii ]: either the specifying be construction, where it is a matter of identifying reasons, or the existential construction, where we're concerned with the existence of reasons. Why alternates with for which, as in the attested example The Physical Training and Recreation Act of 1937 deals with the acquisition of playing fields, which may not be absolutely the [ reason for which ] an authority would wish to acquire property. For which, however, is comparatively rare and formal: it could not idiomatically replace why in ordinary examples like [54].
Also, there's this in CGEL on the bottom of page 1059:
Among the simple relative phrases, whereupon occurs only in supplementary relatives, why only in integrated ones, with reason as antecedent (. . .).
As to fused relatives, there's also this footnote in CGEL on page 1077:
fn 19: Why (which has no counterpart in -ever) appears freely in the interrogative construction, as in This is why I'm leaving, but is marginally possible in the pseudo-cleft: Why I'm leaving is that/because there's no opportunity to use any initiative. It does not occur elsewhere in fused relatives.
From those above CGEL excerpts, that basically means that if the word "why" is a relative word, then it will almost always be in an integrated relative clause that uses the noun "reason" as its antecedent. The few times that a relative "why" isn't part of a normal integrated relative, then, that means that it is a fused relative (which means that there is no separate antecedent for that relative) and will be part of a pseudo-cleft.
So, now let's look at the second part of that dictionary's "relative adverb" definition:
• the reason for which: each has faced similar hardships, and perhaps that is why they are friends.
That definition's example seems to either be using a fused relative in a pseudo-cleft construction (when compared against the info in CGEL) or an embedded interrogative clause. The important part of its example is:
- Perhaps [that] is [why they are friends].
A corresponding clause could be created by replacing the word "that" with its antecedent,
- [That each has faced similar hardships] is perhaps [why they are friends].
That clause has an apparent possible resemblance to a pseudo-cleft and could possibly be interpreted as one. Though, it is more likely that it would be interpreted instead as using an interrogative "why", where the paraphrase could then be,
- That 'each has faced similar hardships' is perhaps the answer to the question 'Why are they friends?'
But in the OP's original example, in the text ("I don't know why") which involves the word "why", it does not use the noun "reason", nor does its construction have the form or shape of a pseudo-cleft. And so, the interrogative word rationale appears to be much more convincing.
NOTE: CGEL is the 2002 reference grammar by Huddleston and Pullum et al., The Cambridge Grammar of the English Language.
Best Answer
The -tion (or -sion) suffix is commonly used to turn a verb into a noun. Some common examples include:
It's true that these nouns are not physical, tangible things, but the definition of noun as "person, place, or thing" is woefully incomplete. These nouns are abstract concepts, which are indeed nouns.