Producer or actor upset about the engineers (7)
I believe the answer is:
creator
'producer' is the definition.
(I've seen this in another clue)
'actor upset about the engineers' is the wordplay.
'upset' indicates an anagram.
'about' means one lot of letters goes inside another.
'the engineers' becomes 're' (abbreviation for Royal Engineers).
'actor' anagrammed gives 'cator'.
'cator' placed around 're' is 'CREATOR'.
'or' is the link.
(Other definitions for creator that I've seen before include "Person who makes or invents things" , "Inventor" , "Originator - God" , "The Almighty" , "Maker" .)