“Hello,” said the drunk (4)
I believe the answer is:
high
'the drunk' is the definition.
(thesaurus)
'hello said' is the wordplay.
'hello' becomes 'hi' ('hi' can be a synonym of 'hello').
'said' indicates a 'sounds like' (homophone) clue.
'hi' sounds like 'HIGH'.
(Other definitions for high that I've seen before include "State of euphoria" , "First-rate - drunk" , "on a trip" , "Eminent; lofty" , "Relatively great or specific elevation" .)