Jester initially impressing court in northern city (6)
I believe the answer is:
yorick
'jester' is the definition.
(I've seen this before)
'initially impressing court in northern city' is the wordplay.
'initially' suggests taking the first letters.
'in' indicates putting letters inside.
'northern city' becomes 'york' (I've seen this before).
The first letters of 'impressing court' is 'ic'.
'ic' put into 'york' is 'YORICK'.
(Other definitions for yorick that I've seen before include "How you amused young prince!" , "Hamlet: 'Alas, poor ......! I knew him, Horatio'" , "Character in 15 down" , "Skull in 'Hamlet'" , "Well-known to Hamlet" .)