Fish out of water without oxygen (4)
I believe the answer is:
dory
'fish' is the definition.
(dory is a kind of fish)
'out of water without oxygen' is the wordplay.
'out of water' becomes 'dry' (as opposed to wet).
'without' is an insertion indicator ('without' can be similar in meaning to 'outside').
'oxygen' becomes 'O' (atomic symbol for oxygen).
'dry' placed around 'o' is 'DORY'.
(Other definitions for dory that I've seen before include "Sea-wolf" , "another fish wanted" , "Golden-yellow fish" , "Marine fish; rowing boat" , "Fish of mackerel family" .)