解き is the 連用形 form of the verb 解く. This can turn the verb into a noun in some cases. Hopefully with the verb 解く you can figure out the intended meaning. I don’t really want to guess since I don’t know anything about the manga and therefore don’t have any context. (Well, I say I don’t want to guess, but just by the definitions on jisho, definition 4 seems most reasonable.)
I would actually agree. The whole plot revolves around a 16-year-old girl who can tell when someone is saying a lie comes to terms with her ability and herself. Thank you for replying and providing some explanation to 解き seanblue.
Dang, I didn’t consider this. That also sounds like it could make sense, but I’m still wrapping my head around grammar, so I can’t 100% confirm it.
A verb in this form doesn’t become an adjective or adjective-like. Another usage of the 連用形 form (besides it being noun-like) is like て form, just used in more formal or literary contexts. It can be used to connect the first of two consecutive actions to the second action. But it can’t be used to modify a noun like an adjective.
In fact, typically if you want a verb to modify a noun similar to an adjective, you’d use a plain form, such as dictionary form, past tense, or negative form. For example, 行く場所 = the place I will go to.
All that said, this is a manga title, so I think they can kind of break the rules a bit if they want. I’m honestly not sure how you’re supposed to interpret 嘘解きレトリック grammatically.
I think the name for the ability in English is ‘discernment’, but that has a religious connotation. I’d probably translate it as something like ‘Lie Detector Rhetoric’, but that might sound too technical, and I don’t know what the ‘rhetoric’ in the series is about, so that translation might be problematic.