Leaves side incomplete (3)
I believe the answer is:
tea
'leaves' is the definition.
(I've seen this before)
'side incomplete' is the wordplay.
'side' becomes 'team' (I've seen this before).
'incomplete' means to remove the last letter.
'team' with its last letter taken off is 'TEA'.
(Other definitions for tea that I've seen before include "Strangely, ate this drink" , "leaves much to be desired?" , "Afternoon meal (3)" , "Cuppa" , "Assam, for instance" .)