Acting legend Cicely (5)
I believe the answer is:
tyson
(Other definitions for tyson that I've seen before include "Mike ..., former US prizefighter" , "American world heavyweight champion, b. 1966" , "Mike --, US boxer" , "US world heavyweight boxing champion, b.1966 -- English fast bowler, d. 2015" , "Undisputed world heavyweight champion, 1987" .)