A little drink and leg-over? (3)
I believe the answer is:
nip
'a little drink' is the definition.
(I've seen this before)
'leg-over?' is the wordplay.
'leg' becomes 'pin' (pin is a kind of leg).
'over?' shows that the letters should be reversed in order (I've seen 'over ' mean this).
'pin' written backwards gives 'NIP'.
'and' acts as a link.
(Other definitions for nip that I've seen before include "Touch of frost" , "Shot" , "Pinch - tot" , "Pinch with small drink" , "Feeling cold" .)