The most common and most likely answer to this crossword clue is the 4 letter word HERO
I've seen this crossword clue in The Times
H
E
R
O
More clues leading to the result HERO
- Champion cutting down murderous king
- Star making a return appearance in Wigmore Hall
- Brave fellow captured by the Roundheads
- Lamp-lighting lover, an illustrious person
- Lead killing the last pair of river birds
- Biblical king finally lacking as leading man
- Lecherous boxing champion
- Male lead is husband, I’m thinking, with nothing on
- He deserves woman’s love
- Old king doesn’t finish idol
Buddy explains!

The straight part
We know that "Champion" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case champion = hero.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.
What does HERO mean?
HERO noun- Somebody who possesses great bravery and carries out extraordinary or noble deeds.
- A role model.
- The protagonist in a work of fiction.
- The current player, especially an hypothetical player for example and didactic purposes. Compare: villain. Not to be confused with hero call.
- A large sandwich made from meats and cheeses; a hero sandwich.
- (food styling) The product chosen from several candidates to be photographed.
- The eye-catching top portion of a web page, sometimes including a hero image; the portion above the fold.