The suffix -ee comes from the French past participle suffix -é(e). There is a relatively short list of English words ending with -ee, the vast majority of which are French or Latin in origin. I suppose killee and givee sound wrong because they’re of Anglo-Saxon origin, not Romantic, so the -ee suffix is less natural.
In general, I would avoid using -ee to coin new words, and further avoid using -ee words other than the most common, such as employee, attendee, detainee, &c. The silliest-sounding -ee words seem to be those using native English roots, where -ed is better:
*The mugger mugs the muggee.
The mugger mugs the mugged.
Is there a standard rule to decide which one to use, "-ian" or "-ist",
when describing an occupation?
The suffix in mathematician and physician (and other words such as politician, magician) is actually -ician (from the French -icien) which is constructed by taking the suffix -ica (names of arts or sciences in Latin such as: magica, mathematica, politica etc) and "adding" -ian to the -ica suffix (I write "adding" because the "a" is dropped from -ica):
magica -> mag-ica -> mag-ic(a)-ian.
So, the suffix -ician means someone who is a specialist or practitioner.
(Also the -ician rule also sometimes - confusingly though, not always - applies to such words which don't end in -ica but instead just -ic, such as: academic becomes academ-ic -> academ-ician and the same for geometr-ic: geometr-ician.)
As for the specialist words ending with -ist (linguist, chemist), I am not sure, but I think the Latin word stems for these words end in just -a rather than -ica: chemista (chimista?) and lingua. I think these -a word stems get the -ist suffix, from the French -iste or Latin -ista. (agential suffix)
How to tell if we want to invent some new terms? For example, if I
proved a new theorem using some idea from Newton, do I call the proof
Newton's argument or Newtonian argument?
[...]
Can "-ian" be used interchangeably in "I am a Kantian" and "This is a
Kantian style argument."? or there is some tradition for each word
ending with "-ian"? i.e., Some words ending with "-ian" can be only
used as noun or adj.
Here I am not as sure. The suffix -an means "pertaining to," from Latin -anus, in some cases via French -ain, -en. I cannot explain the added "i" in Newton-i-an. Maybe it is added to make the word sound better than just "Newtonan".
Best Answer
Actually dragee is in the dictionary: it's a fruit or nut wrapped in sugar (a peanut M&M is a dragee). But anyway!
I would say that if there are no existing words that fit the purpose (as in the case of a dragged object in computing), and the word 'sounds right', then there is no problem with neologising. After all, if no new words came along the language would never evolve.