Is stuck in very warm lift (5)
I believe the answer is:
hoist
'lift' is the definition.
('hoist' can be a synonym of 'lift')
'is stuck in very warm' is the wordplay.
'stuck in' means one lot of letters goes inside another.
'very warm' becomes 'hot' (I've seen this before).
'is' placed within 'hot' is 'HOIST'.
(Other definitions for hoist that I've seen before include "Wind up" , "Winch" , "group of flags" , "Come down" , "Lifting tackle" .)