Love divine is out of the ordinary (3)
I believe the answer is:
odd
'out of the ordinary' is the definition.
'love divine' is the wordplay.
'love' becomes 'o' (In tennis, 'love' means 'zero').
'divine' becomes 'dd' (divine can mean theologian eg Doctor of Divinity).
'o'+'dd'='ODD'
'is' acts as a link.
(Other definitions for odd that I've seen before include "like half the numbers?" , "Peculiar sort of number?" , "Peculiar in uneven way" , "Number not divisible by two" , "Not matching" .)