One of our Figaristas wrote us this question: I heard this on my local public radio station today. Is there a name for this type of infelicity?
…complained that the law unfairly lets recreational fishermen off the hook.
Given that the news writer or person quoted was probably being intentional, we’d mark it down as an ironic trope. “Off the hook” is an idiom that, when applied to the literal hook, takes on the dual resonance of a pun. An unintended usage would be termed a hypallage, an unintended agreement or mishmash of words.
If any offense has been committed, it’s against fishing. Anyone who has ever caught a fish knows that you don’t just let it off the hook. Removing a hook from a fish requires an operation with a surgeon’s skill. Whoever invented that idiom in the first place, we’re guessing, spent a lot of time indoors.