Agam

A complicated Scottish Gaelic "verb" that is technically a preposition "at me" but commonly means translates to "I have"

Friend 1: Tha ceann goirt agam
Friend 2: Actually, in this situation you would use "orm (on me)" instead of "agam (at me)" because your head is always on you, you fucking idiot
Friend 1: The caraid dona agam

subdermatoglyphic

The longest word in the English language that doesn't use any letters twice.

Phil: "Hey man, did you know 'subdermatoglyphic' is the longest word in the English language that doesn't use any letters twice"
Matt: "Get a life, nerd"