Stirrer good with big drink (6)
I believe the answer is:
gossip
'stirrer' is the definition.
(someone who stirs up gossip)
'good with big drink' is the wordplay.
'good' becomes 'g' (abbreviation).
'with' means one lot of letters go next to another.
'big' becomes 'os'.
'drink' becomes 'sip' (sipping is a kind of drinking).
'g'+'os'+'sip'='GOSSIP'
(Other definitions for gossip that I've seen before include "'Rumours, scandal (6)'" , "Idle and mildly malicious talk" , "Loose malicious talk" , "female friend at a birth" , "Idle, malicious, chatter" .)