Look displeased as small animal left (5)
I believe the answer is:
scowl
'look displeased' is the definition.
(I've seen this in another clue)
'small animal left' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'animal' becomes 'cow' (cow is a kind of animal).
'left' becomes 'l' (common abbreviation).
's'+'cow'+'l'='SCOWL'
'as' acts as a link.
(Other definitions for scowl that I've seen before include "Glower; frown" , "Frown with displeasure" , "Angry frown" , "Look angry" , "dirty look" .)