The most common and most likely answer to this crossword clue is the 8 plus 3 letter word MUHAMMAD ALI
I've seen this crossword clue in Independent
M
U
H
A
M
M
A
D
A
L
I
More clues leading to the result MUHAMMAD ALI
Buddy explains!
The straight part
We know that "legend?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case legend? = muhammad ali.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.