Loyalty of priest and skilled worker joining craft (12)
I believe the answer is:
partisanship
'loyalty' is the definition.
(loyalty to a cause)
'priest and skilled worker joining craft' is the wordplay.
'priest' becomes 'p' (ecclesiastical abbreviation).
'and' says to put letters next to each other.
'skilled worker' becomes 'artisan' (an artisan is a skilled craftsperson).
'joining' is a charade indicator (letters next to each other).
'craft' becomes 'ship' (ship is a kind of craft).
'p'+'artisan'+'ship'='PARTISANSHIP'
'of' is the link.
(Other definitions for partisanship that I've seen before include "Factionalism" , "Taking sides" , "One-sided support" .)