Be first individual to enter wharf (7)
I believe the answer is:
pioneer
'be first' is the definition.
(thesaurus)
'individual to enter wharf' is the wordplay.
'individual' becomes 'one' (an individual is one person).
'to enter' is an insertion indicator.
'wharf' becomes 'pier' (I've seen this before).
'one' put inside 'pier' is 'PIONEER'.
(Other definitions for pioneer that I've seen before include "Open up an area" , "first time in the field" , "First to explore a new area" , "Original developer" , "make the first move!" .)