One in cool air over squid (8)
I believe the answer is:
'squid' is the definition.
('calamari' can be a synonym of 'squid')
'one in cool air over' is the wordplay.
'one' becomes 'a'.
'in' indicates putting letters inside.
'cool' becomes 'calm' (I've seen this before**).
'over' is an anagram indicator.
'a' inserted inside 'calm' is 'calam'.
'air' is an anagram of 'ari'.
(Other definitions for calamari that I've seen before include "Mediterranean cooked squid" , "Squid prepared as food" , "Squid served as food" , "Battered squid rings" , "Dish of squid" .)