Carefree youth with a woman trapping American lawyer on board a ship (5,4)
I believe the answer is:
salad days
'carefree youth' is the definition.
(I've seen this before)
'a woman trapping american lawyer on board a ship' is the wordplay.
'woman' becomes 'lady' (lady is a kind of woman**).
'trapping' is an insertion indicator.
'american lawyer' becomes 'da' (abbreviation for District Attorney).
'on board' is an insertion indicator.
'a ship' becomes 'ss'.
'lady' placed around 'da' is 'ladday'.
'a'+'ladday'='aladday'
'aladday' put within 'ss' is 'SALAD DAYS'.
'with' acts as a link.
(Other definitions for salad days that I've seen before include "inexperienced youth" , "times when she was young" , "when one is young?" , "Time for a vegetarian diet" , "Carefree youth" .)