Reasonable means that whatever decision was made is appropriate given the particular circumstances, and most would regard it as so.
Justified means that whatever decision was made is done for a good reason, in the interest of fairness.
There are times the words could be used interchangeably, and contexts where the difference is subtle. It all depends on the nature of the request or issue at hand.
I might use "justified" if I was angry about something, and was acting in response:
Was it polite to skip their wedding after they insulted me like that? No, but I think my decision was justified.
I might use "reasonable" if I think everyone would agree that there was nothing else that could be done:
Was I happy about missing their wedding so that I could go to my mother's funeral? No, but I think my decision was reasonable.
But there are contexts where either word will work just fine:
You said that you'd deliver the cake before noon, but it didn't get here until 3 o'clock. I think my request for a refund is reasonable/justified.
In that sentence, reasonable would work because most people would agree that a refund would be appropriate given the circumstances, and justified would work because the request is fair.
Good question! They are not synonyms. I will try to explain the differences the best I can.
The first difference is that "Allegation" is a noun, and "Blame" is usually a verb. Blame can also a noun, but I think it is more common to use it as a verb. "Allegation" means "A claim that someone is guilty" (noun) and "Blame" means "to claim that someone is guilty" (verb). So the differences between your two definitions come down to the difference between claim as a verb and claim as a noun. Google gives the verb definition as
State or assert that something is the case, typically without providing evidence or proof.
and also gives the noun definition as:
An assertion of the truth of something, typically one that is disputed or in doubt.
So if I were to Claim (verb) that I just won the lottery, I stated or asserted that I won the lottery. I also made a claim (noun) that I just won the lottery. I made an assertion of the fact that I won the lottery.
Now as for "blame" as a noun, the differences are more obvious. "Blame" as a noun is synonymous with "guilt". If someone makes allegations that I am guilty, it is still a possibility that I am innocent. That only means that someone says that I am guilty. The same is true if someone blames (verb) me. However, if "The blame is on me" or "I take the blame" (both nouns) then it does not leave an option that I am innocent. It means that I am guilty.
Best Answer
Formally, we use accuse with an act—we assert that somebody did something reprehensible:
But we use blame with the outcome—we assert somebody's responsibility for the undesirable result:
Informally, however, these distinctions often blur. For instance, if the robbery has already been mentioned, blame may very easily take a for clause which explains why the target is blamed:
And accuse may take a complement which expresses a state rather than an act: