Ill-fated jester, one caught entering northern city (6)
I believe the answer is:
yorick
'ill-fated jester' is the definition.
'yorick' can be an answer for 'jester' (I've seen this before). I'm not sure about the 'ill-fated' bit.
'one caught entering northern city' is the wordplay.
'one' becomes 'i' (Roman numeral).
'caught' becomes 'c' (cricket abbreviation).
'entering' indicates putting letters inside.
'northern city' becomes 'york' (I've seen this before).
'i'+'c'='ic'
'ic' going inside 'york' is 'YORICK'.
Can you help me to learn more?
(Other definitions for yorick that I've seen before include "How you amused young prince!" , "Funny fellow" , "Dead jester in Hamlet" , "said to be poor" , "White-face clown" .)