Girl gets lad in trouble (5)
I believe the answer is:
linda
'girl' is the definition.
'lad in trouble' is the wordplay.
'trouble' is an anagram indicator.
'lad'+'in'='ladin'
'ladin' anagrammed gives 'LINDA'.
'gets' acts as a link.
(Other definitions for linda that I've seen before include "lady" , "-- Gray, 'Dallas' star" , "Girl's name (I, not Y)" , "girl" , "- Ronstadt, US singer" .)