Influence western rowing crew (6)
I believe the answer is:
weight
'influence' is the definition.
(thesaurus)
'western rowing crew' is the wordplay.
'western' becomes 'w'.
'rowing crew' becomes 'eight' (I've seen this before).
'w'+'eight'='WEIGHT'
(Other definitions for weight that I've seen before include "Vertical force exerted by a mass" , "Burden" , "Importance, oppressive force" , "Importance, heaviness" , "Vertical force as a result of gravity" .)