Wild when a fellow given time is at large (5)
I believe the answer is:
feral
'wild' is the definition.
('feral' can be similar in meaning to 'wild')
'a fellow given time is at large' is the wordplay.
'a fellow' becomes 'f' (abbreviation - of a society etc.).
'given' is a charade indicator (letters next to each other).
'time' becomes 'era' (I've seen this before**).
'is at' is a charade indicator (letters next to each other).
'large' becomes 'l'.
'f'+'era'+'l'='FERAL'
'when' is the link.
(Other definitions for feral that I've seen before include "Wild, untamed" , "(Of an animal) running wild" , "Wild or brutal" , "'Savage, wild (5)'" , "Wild but originally domestic" .)