What does ...なくはない mean?

Question

Initial searching in Japanese-Japanese dictionaries seem to suggest that it's along the lines of "has a bit of ..., so saying otherwise would be wrong", "more so than not", and is a synonym to ないわけではない (though I personally don't really understand ないわけではない either).

Am I understanding it correctly? What would be an accurate and/or good way (these might not be the same) to translate it to English when it's part of a sentence, or is it something that's heavily context-dependent? Would it be something like "it's not that [negative clause]"?

While I do have a specific example of it being used that I'm interested in, I'm also interested in the general case.

P.S., A fan translation of that example translated it as "Unfortunately yes". Is this a good translation? Does the expression itself convey the exasperation, or is it simply in the tone it's said?

Answer 1

As far as I'm aware, なくはない is a double negative with the meaning being something like, "it's not that (whatever was said) is not the case" with the implication "(whatever was said) may be true, but there is some issue with plainly stating 'yes.'" So I guess "not no" is a good way to think about it.

I personally wouldn't have translated that as "unfortunately, yes." I might have gone with something like, "it's not like he can't do it." In this case she happens to be exasperated because of her relationship with the character in question (I happen to have read this manga), but the phrase isn't specifically tailored for exasperation.

Answer 2

わけではない is used when you're in a situation, or in regards to something that someone else has said, to indicate the belief that although something might seem to be the case, this may not hold true; however, it often can, depending on the context, be used by speakers to simply deny things in a less direct (euphemistic or roundabout) way to try to address the face needs of the interlocutor. For example, in a sentence like "金がすべてというわけではない"/"Money isn`t everything.", it's clear that the speaker is denying the statement. (There are more examples at jgram).

The strength of the negation can be increased by using "別に" e.g. as in "別に病んでるわけではない". わけではない can also be used to mean that something has some truth, but is not binary.

It means "may not necessarily be the case that it's not...": the 訳{わけ} in わけではない refers to something meaning something, being the case that, being the circumstances that ... etc.

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However, with なくはない, my dictionary says that it means 全くないわけではない ("not like it's entirely not") and that it also implies something can occur/take place, so I believe it isn't quite a synonym of ないわけではない. I haven't seen this as much as （ない）わけではない, but the 実用日本語表現辞典 says that it tends to more often be used in a way which has negative connotations, even if it doesn't necessarily convey exasperation.