The Pedant's dilemma:

when one of the lesser people, exasperated with your punctilious and picky-pants demeanour, mistakenly calls you a pendant... which is the more appropriate course of action to pursue - to simply let the mistake slide and smirk to oneself or to correct their word choice, in the process confirming the intent of their utterance?

Really, what is playing on others' mistakes or ignorance for if not a spot of fun? I recommend you find a cord or fixture somewhere nearby from which you can dangle decoratively, all the while extolling your pendantly qualities. After you explain yourself chances are good they'll never misuse the word again, beyond which any excuse to hang about in public places is a good one to seize up.