Turn of old French actor performing after end of war (8)
I believe the answer is:
'turn' is the definition.
(rotation is a kind of turn)
'old french actor performing after end of war' is the wordplay.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'french actor' becomes 'tati' (Jacques Tati).
'performing' becomes 'on' (I've seen this in other clues).
'after' means one lot of letters go next to another.
'end of' says to take the final letters.
The final letter of 'war' is 'r'.
'otation' put after 'r' is 'ROTATION'.
'of' acts as a link.
(Other definitions for rotation that I've seen before include "Revolutionary movement" , "altering of crops" , "Turning motion" , "Action of turning" , "The action of moving around an orbit" .)