"Iron Mike" (5)
I believe the answer is:
tyson
'iron mike' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for tyson that I've seen before include "US world heavyweight boxing champion, b.1966 -- English fast bowler, d. 2015" , "Undisputed world heavyweight champion, 1987" , "Youngest ever undisputed world heavyweight boxing champion, b, 1966" , "Mike --, US boxer" , "Mike ..., former US prizefighter" .)