Desire for food Dad's shown on return — pretty small? (8)
I believe the answer is:
appetite
'desire for food' is the definition.
(I've seen this before)
'dad's shown on return pretty small?' is the wordplay.
'dad' becomes 'pa' (both can mean one's father).
'shown on return' says the letters should be written backwards.
'pretty small?' becomes 'petite' (petite can mean small and delicate).
'pa' in reverse letter order is 'ap'.
'ap'+'petite'='APPETITE'
(Other definitions for appetite that I've seen before include "enthusiasm" , "Desire, relish" , "Desire or liking, for power or food" , "thirst" , "Physical need for food" .)