Sunbathe with a drink after time getting fit (7)
I believe the answer is:
tantrum
'fit' is the definition.
(synonyms)
'sunbathe with a drink after time' is the wordplay.
'sunbathe' becomes 'tan' (I've seen this in another clue).
'with' says to put letters next to each other.
'a drink' becomes 'rum' (rum is a kind of drink).
'after' is a charade indicator (letters next to each other).
'time' becomes 't' (abbreviation).
'rum' put after 't' is 'trum'.
'tan' next to 'trum' is 'TANTRUM'.
'getting' is the link.
(Other definitions for tantrum that I've seen before include "Childish fit of anger" , "Frenzy" , "Child's outburst of bad temper" , "Childish outbreak of temper" , "Burst of temper" .)