Comatose fellow coming in walked the wrong way (7)
I believe the answer is:
dormant
'comatose' is the definition.
(I've seen this before)
'fellow coming in walked the wrong way' is the wordplay.
'fellow' becomes 'man' (fellow can mean a man).
'coming in' is an insertion indicator.
'walked' becomes 'trod' (treading is a kind of walking).
'the wrong way' says the letters should be written backwards.
'trod' written backwards gives 'dort'.
'man' put into 'dort' is 'DORMANT'.
(Other definitions for dormant that I've seen before include "Sleeping or inactive, say volcano" , "Comatose" , "Suspended" , "asleep" , "Mordant about lying inactive" .)