Wild fellow, real wild (5)
I believe the answer is:
feral
'wild' is the definition.
(similar in meaning)
'wild fellow real' is the wordplay.
'wild' is an anagram indicator.
'fellow' becomes 'f' (abbreviation - of a society etc.).
'f'+'real'='freal'
'freal' anagrammed gives 'FERAL'.
(Other definitions for feral that I've seen before include "Escaped-into-wild (animal)" , "Wild, untamed" , "Of plants or animals, wild" , "Wild (though once tame)" , "beastly" .)