Frolics happily, given drink aboard ship (6)
I believe the answer is:
sports
'frolics happily' is the definition.
'drink aboard ship' is the wordplay.
'drink' becomes 'port' (I've seen this before**).
'aboard' is an insertion indicator.
'ship' becomes 'ss'.
'port' placed within 'ss' is 'SPORTS'.
'given' acts as a link.
(Other definitions for sports that I've seen before include "Wears (a noticeable item)" , "Football, tennis etc." , "Eg, football, cricket" , "Soccer and rugby, say" , "Back page journalist" .)