Uncomfortable allies ate messily (3,2,4)
I believe the answer is:
ill at ease
'uncomfortable' is the definition.
(being ill at ease is being uncomfortable or uneasy)
'allies ate messily' is the wordplay.
'messily' indicates anagramming the letters.
'allies'+'ate'='alliesate'
'alliesate' is an anagram of 'ILL-AT-EASE'.
(Other definitions for ill at ease that I've seen before include "Unable to relax" , "Unsettled, anxious" , "Fidgety" , "Embarrassed" , "discomfited" .)