correct, just

当前(あたりまえ)	Less formal. Has the nuance of, ‘Just or correct because it’s normal.’ $$$

当然(とうぜん)	More formal. Unlike 当たり前、当然 has the nuance of ‘correct because it is natural, as God intended.’ “Men are stronger than women so only men should be allowed in the army – it’s only natural.” “I’ve come for what is mine!” “If he built the house, he should be paid for it – it’s only right.”

適当(てきとう)	Appropriate, as in an appropriate gift. But – incredibly – 適当also means irresponsible! Doing something without considering the consequences. Example:適当な人間だ！ “He’s irresponsible. He’ll say anything that pops into his head.”

正しい(ただしい)	Correct, in BOTH senses:literally, as in a correct answer. (unlike 適当、　正しいimplies that there is ONLY ONE correct one (after all there might be several appropriate gifts for a person!)). And figuratively:something that is morally correct or just.

適切(てきせつ)	A more mild version of 適当. 　適切 is more like, It’s appropriate enough to get the job done, but not ideal.

妥当(だとう)	More half-assed than 適切 or 正しい... 妥当 is like, barely adequate. It’ll do. TTT

もっともの	Reasonable. Not perfect or just. もっとも is closer to 妥当。

正に(まさに)	Exactly (what he wanted all along), positively (the case), perfectly (fits the image).