Parched having to swallow cold bitter (5)
I believe the answer is:
acrid
'bitter' is the definition.
(thesaurus)
'parched having to swallow cold' is the wordplay.
'parched' becomes 'arid' (I've seen this before).
'having to swallow' indicates putting letters inside.
'cold' becomes 'c' (eg on taps).
'arid' enclosing 'c' is 'ACRID'.
(Other definitions for acrid that I've seen before include "Having a bitter smell or taste" , "Strong and sharp-smelling" , "causing corrosion" , "Sour, pungent" , "Bitter in smell, like smoke" .)