Social worker given drink in chamber (6)
I believe the answer is:
antrum
'chamber' is the definition.
(I've seen this before)
'social worker given drink' is the wordplay.
'social worker' becomes 'ant' (ants are social insects).
'given' says to put letters next to each other.
'drink' becomes 'rum' (rum is a kind of drink).
'ant'+'rum'='ANTRUM'
'in' acts as a link.
(Other definitions for antrum that I've seen before include "Bodily cavity as in the nose" , "Bodily cavity or chamber" , "Cavity within a bone, like sinus in upper jaw" .)