Explain clue I cracked with girlfriend, perhaps (9)
I believe the answer is:
elucidate
'explain' is the definition.
(I know this)
'clue i cracked with girlfriend perhaps' is the wordplay.
'cracked' indicates an anagram.
'with' is a charade indicator (letters next to each other).
'girlfriend perhaps' becomes 'date' (I've seen this before).
'clue'+'i'='cluei'
'cluei' is an anagram of 'eluci'.
'eluci'+'date'='ELUCIDATE'
(Other definitions for elucidate that I've seen before include "Make clear and more comprehensible" , "Shed light on, clarify" , "Make clear, explain" , "Shed light upon" , "Throw light on a problem, make clear (9)" .)