Minor actor helping to win Oscar for project (11)
I believe the answer is:
extrapolate
'project' is the definition.
(thesaurus)
'minor actor helping to win oscar' is the wordplay.
'minor actor' becomes 'extra' (I've seen this before).
'helping' becomes 'plate'.
'to win' means one lot of letters goes inside another.
'oscar' becomes 'o' (phonetic alphabet: alpha, bravo, charlie etc.).
'plate' enclosing 'o' is 'polate'.
'extra'+'polate'='EXTRAPOLATE'
'for' acts as a link.
(Other definitions for extrapolate that I've seen before include "Conclude from other data" , "forecast" , "Infer further points from trends in data" , "Infer from what's known - to repeal tax (anag)" .)