... in Isle of Man (3)
I believe the answer is:
leo
'man' is the definition.
(I've seen this before)
'in isle of' is the wordplay.
'in' indicates a hidden word.
'LEO' is hidden within 'isle of'.
(Other definitions for leo that I've seen before include "Astrological sign" , "one of several popes" , "Lion constellation" , "born in July or August" , "Man" .)