He could be nailed (6)
I believe the answer is:
daniel
'he' is the definition.
'could be nailed' is the wordplay.
'could be' indicates anagramming the letters.
'nailed' anagrammed gives 'DANIEL'.
(Other definitions for daniel that I've seen before include "-- Defoe; -- Barenboim" , "Old Testament book" , "-- Deronda (Eliot)" , "Hebrew prophet rescued from lion's den" , "Lions' den survivor" .)