Of the many words I love, “quiddity” as been very close to the top of the list since I discovered it. I forget the context, but I feel like it was a summer or two ago, it came up (I have no idea how or why) when I was visiting the parents. My mom was looking it up, but I tried to guess what it meant from my smidgie of Latin: I guessed “what-ness” or “thingitude”. I was close:

quid di ty (kwi(d’i(-te-) pronunciation
n., pl. -ties.

  1. The real nature of a thing; the essence.
  2. A hairsplitting distinction; a quibble.

Or even better, from WordNet,

The noun quiddity has 2 meanings:

  1. Meaning #1: an evasion of the point of an argument by raising irrelevant distinctions or objections
    Synonym: quibble
  2. Meaning #2: the essence that makes something the kind of thing it is and makes it different from any other

On the Latin theme, I may start writing error messages in Latin after reading this.