Playful serenade after drink (7)
I believe the answer is:
teasing
'playful' is the definition.
(similar in meaning)
'serenade after drink' is the wordplay.
'serenade' becomes 'sing' (I've seen this before).
'after' says to put letters next to each other.
'drink' becomes 'tea' (tea is a kind of drink).
'sing' put after 'tea' is 'TEASING'.
(Other definitions for teasing that I've seen before include "Combing wool and irritating playfully" , "Tantalising" , "Making fun of in a playful way" , "Making fun of (someone)" , "flirting maybe" .)