When a film or television character is always remembered for an entirely irrelevant trait.
This trope is named for Sally Acorn from Sonic the Hedgehog who, despite being one of the most plot-developed characters in the comic/show, is only remembered for being naked.
1. In the English language, an instance of the word "this" which lacks a referent, i.e. some other word which explains what the "this" in question refers to. Lacking a referent, the "this" is thus "naked" and may prove confusing to the reader or listener, since they do not know precisely to what the writer or speaker is referring.
Sue: I really hate this.
John: Really hate what? You employed a "naked this" there so I don't know what you are talking about.
Sue: Oh, well excuse me, Mr. University of Dickishness. Fine. I hate this Grammar Nazi kick you've been on lately. Is that better, fuckface?