After Friday hear he will leave monk (5)
I believe the answer is:
friar
'monk' is the definition.
(I've seen this before)
'after friday hear he will leave' is the wordplay.
'after' says to put letters next to each other.
'friday' becomes 'fri' (synonyms).
'will leave' suggests deleting specific letters.
'hear' with 'he' taken away is 'ar'.
'fri' next to 'ar' is 'FRIAR'.
(Other definitions for friar that I've seen before include "Male member of a mendicant religious order" , "he offers religious teaching?" , "Religious man" , "Member of one of the four mendicant orders" , "Eg, a Franciscan" .)