Meet knight in Eastern bar (9)
I believe the answer is:
encounter
'meet' is the definition.
('encounter' can be a synonym of 'meet')
'knight in eastern bar' is the wordplay.
'knight' becomes 'n' (chess).
'in' means one lot of letters goes inside another.
'eastern' becomes 'e'.
'bar' becomes 'counter' (I've seen this before**).
'e'+'counter'='ecounter'
'n' put into 'ecounter' is 'ENCOUNTER'.
(Other definitions for encounter that I've seen before include "Unexpected meeting" , "Come upon, meet" , "See 19" , "Bump into" , "Meet; confrontation" .)