Fit plug to the point (5)
I believe the answer is:
adapt
'fit' is the definition.
(thesaurus)
'plug to the point' is the wordplay.
'plug' becomes 'ad' (Advertisement plugs products).
'to the point' becomes 'apt' (I've seen this before).
'ad'+'apt'='ADAPT'
(Other definitions for adapt that I've seen before include "Change to suit a new purpose" , "Change to suit a different purpose" , "Become adjusted to new circumstances" , "Alter, amend" , "Put to particular use" .)