Heavyweight great (3)
I believe the answer is:
ali
'heavyweight great' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for ali that I've seen before include "Son-in-law to Muhammad" , "Person" , "Mohammad . . ., . . . Hewson" , "Former boxing champion" , "Lepidopterous floater, apian stinger, d. 2016" .)