Liveliness in frisky priest (6)
I believe the answer is:
esprit
'liveliness' is the definition.
(esprit is a kind of liveliness)
'frisky priest' is the wordplay.
'frisky' indicates anagramming the letters.
'priest' with letters rearranged gives 'ESPRIT'.
'in' is the link.
(Other definitions for esprit that I've seen before include "What good corps needs" , "Sprightliness" , "wit from France" , "... de corps, team spirit" , "Sparkling quality" .)