Leader of Society meeting Queen, loathsome and obsequious (7)
I believe the answer is:
servile
'obsequious' is the definition.
('servile' can be similar in meaning to 'obsequious')
'leader of society meeting queen loathsome' is the wordplay.
'leader of' indicates taking the first letters.
'meeting' is a charade indicator (letters next to each other).
'queen' becomes 'er' (abbreviation for Elizabeth Regina).
'loathsome' becomes 'vile' (I've seen this before).
The initial letter of 'society' is 's'.
's'+'er'+'vile'='SERVILE'
'and' is the link.
(Other definitions for servile that I've seen before include "Fawning, slavish" , "Toadying" , "Slave-like" , "Excessively eager to please" , "Menial, excessively submissive" .)