Chief caught king out (4)
I believe the answer is:
head
'chief' is the definition.
(I know that chief can be written as head)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for head that I've seen before include "Person in charge" , "Leader; water pressure" , "''and still the wonder grew / That one small ... could carry all he knew'' (Goldsmith)" , "Beer foam; front" , "Edible part of cabbage" .)