"いまいち" vs "物足りない" meaning / usage?


Both `いまいち` and `物足りない` generally mean that something is lacking, not good
enough. Frequently, the undertone is that this is due to the inadequacy of the
speaker.

`いまいち` is sort of slang, but still ok for business conversations.

Based on context, natives have a sense for which sounds natural. But, for the
most part, they are interchangeable.

Am I wrong on any of those points?




As the OP says, both いまいち and 物足りない mean that something is lacking, or
insufficient. However, いまいち doesn’t make a sentence by its own, while 物足りない
makes a sentence if you add 何か, which can be interpreted as either a pronoun,
something or adverb, somewhat, or a subjective word to it.

いまいち is a shorter form of 今一つ, literally meaning “another one (required),” and
いまいち can be used in such a way as

この携帯のデザインはいまいちですね – The design of this mobile phone isn’t there yet.

彼を課長にするにはいまいちだなア – He isn’t qualified to be promoted to the unit manager yet.

However, いまいち is too colloquial to be used in a written form. You’d better
limit its use to an informal conversation.




いまいち or いまひとつ is "not very good", and 物足りない is "something is left to be
desired". It might be true that in most situations you can use either one you
can use the other one too, but I still don't dare say they have the same
meaning.

They're all about dissatisfaction towards the mentioned, and have nothing to
do with the speaker's quality, or humbleness.

いまいち was originally a slang, but no longer sounds particularly slangy. But yes
it's still colloquial, so you should avoid to use it in formal documents.

