Attempt to guard goal with it (6)
I believe the answer is:
trendy
'with it' is the definition.
(thesaurus)
'attempt to guard goal' is the wordplay.
'attempt' becomes 'try' (I've seen this before).
'to guard' is an insertion indicator.
'goal' becomes 'end' ('end' can be a synonym of 'goal').
'try' placed around 'end' is 'TRENDY'.
(Other definitions for trendy that I've seen before include "With-it" , "Informally in the latest fashion" , "Modish" , "following latest convention" , "'Hip, fashionable (6)'" .)