Virus getting hospital department flowing (6)
I believe the answer is:
fluent
'flowing' is the definition.
(synonyms)
'virus getting hospital department' is the wordplay.
'virus' becomes 'flu' (influenza).
'getting' is a charade indicator (letters next to each other).
'hospital department' becomes 'ENT' (abbreviation for Ear, Nose and Throat department).
'flu'+'ent'='FLUENT'
(Other definitions for fluent that I've seen before include "Speaking or writing easily (in a language)" , "Ready in speech" , "Easy with words" , "Easily flowing" , "Free-flowing" .)