There’s nothing odd in priest’s idea to marry again (5)
I believe the answer is:
retie
'marry again' is the definition.
('tie' can be a synonym for 'marry' so perhaps 'retie' is OK for 'marry again')
'there's nothing odd in priest's idea' is the wordplay.
'there's' means one lot of letters go next to another.
'nothing odd in' means one should take alternating letters (only the letters in even-numbered positions).
'idea' becomes 'ie' (I am not sure about this - if you are sure you should believe this answer much more).
The alternate letters of 'priests' are 'ret'.
'ret' put next to 'ie' is 'RETIE'.
'to' acts as a link.
Can you help me to learn more?
(Other definitions for retie that I've seen before include "Make knot or bow again" , "Link up again" , "make another knot" , "Bind again" , "restore connection" .)