Arrogant poster might be this (5-2)
I believe the answer is:
stuck-up
I believe this is a double definition.
'arrogant' is the first definition.
(thesaurus)
'poster might be this' is the second definition.
(eg a poster might be stuck on a wall)
(Other definitions for stuck-up that I've seen before include "Snooty" , "Hoity-toity" , "Snobbish, proud" , "Overly conceited or arrogant" , "Toffee-nosed" .)