Pat reels about and departs drunk (9)
I believe the answer is:
plastered
'drunk' is the definition.
(slang term)
'pat reels about and departs' is the wordplay.
'about' indicates an anagram.
'and' says to put letters next to each other.
'departs' becomes 'd' (abbreviation eg in train timetables).
'pat'+'reels'='patreels'
'patreels' with letters rearranged gives 'plastere'.
'plastere'+'d'='PLASTERED'
(Other definitions for plastered that I've seen before include "Coated thickly, being slangily drunk" , "Paralytic (slang)" , "Intoxicated" , "Pickled" , "Rendered" .)