Be in a huff (4)
I believe the answer is:
sulk
'be in a huff' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for sulk that I've seen before include "Mood of sullen aloofness" , "Be silent and resentful" , "Be silently bad-tempered" , "Fit of bad temper" , "Act aloof" .)