Let an Irish priest on X? (8)
I believe the answer is:
tenanted
'let an irish priest on x?' is the definition.
I can't judge whether this definition defines the answer.
'priest on x?' is the wordplay.
'priest' becomes 'anted' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'on' means one lot of letters go next to another.
'x?' becomes 'ten' (X is the Roman numeral for ten).
'anted' after 'ten' is 'TENANTED'.
Can you help me to learn more?
(Another definition for tenanted that I've seen is " Occupied for rent".)