He gets it wrong a lot (3)
I believe the answer is:
tim
'he' is the definition.
(short for Timothy)
'it wrong a lot' is the wordplay.
'wrong' is an anagram indicator.
'a lot' becomes 'm'.
'it' anagrammed gives 'ti'.
'ti'+'m'='TIM'
'gets' acts as a link.
(Other definitions for tim that I've seen before include "Adjoin" , "Tiny chap" , "-- Brooke-Taylor, comic" , "Little fellow" , "Tiny ..., endearing Dickens boy" .)