The Collaborative International Dictionary of English v.0.48:

Uppish \Up"pish\, a. [From Up.]
   Proud; arrogant; assuming; putting on airs of superiority.
   [Colloq.] --T. Brown. -- Up"pish*ly, adv. [Colloq.] --
   Up"pish*ness, n. [Colloq.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

uppish
    adj 1: (used colloquially) overly conceited or arrogant; "a
           snotty little scion of a degenerate family"-Laurent Le
           Sage; "they're snobs--stuck-up and uppity and
           persnickety" [syn: bigheaded, persnickety, snooty,
           snot-nosed, snotty, stuck-up, too big for one's
           breeches, uppish]