Failure of a person nearer losing head (5)
I believe the answer is:
loser
'failure of a person' is the definition.
(a pathetic or hopeless person)
'nearer losing head' is the wordplay.
'nearer' becomes 'closer' ('close' can be similar in meaning to 'near').
'losing head' means to remove the first letter.
'closer' with its first letter taken away is 'LOSER'.
(Other definitions for loser that I've seen before include "One who is (always) unsuccessful" , "Roles for a non-winner" , "No-hoper" , "Person who's a failure" , "Someone who fails consistently" .)