____ X was a human rights activist, assassinated in 1965 (7)

I believe the answer is:
malcolm
(Other definitions for malcolm that I've seen before include "- Bradbury, Br. author" , "- Bradbury, Eng. writer" , "- X, American civil rights leader" , "King after Macbeth (Shak.)" , "King at end of Macbeth" .)