Keenness from king entering in urban style? (8)
I believe the answer is:
alacrity
'keenness' is the definition.
(thesaurus)
'king entering in urban style?' is the wordplay.
I cannot really understand how this works, but
'king' could be 'cr' (short for Carolus Rex, King Charles in Latin) and 'cr' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
'from' is the link.
Can you help me to learn more?
(Other definitions for alacrity that I've seen before include "Enthusiastic speed" , "Eager haste" , "Brisk and cheerful readiness" , "Expedition" , "'Briskness, promptness (8)'" .)