Suffer no fool: Canute misquoted about heresy, initially (4)
I believe the answer is:
ache
'suffer' is the definition.
(synonyms)
'no fool canute misquoted about heresy initially' is the wordplay.
'no' indicates named letters should be taken away.
'fool' becomes 'nut'.
'misquoted' indicates an anagram (an inaccurate or mistaken spelling).
'about' is an insertion indicator.
'heresy initially' becomes 'h' (I can't justify this - if you can you should give a lot more credence to this answer).
'canute' with 'nut' taken away is 'cae'.
'cae' is an anagram of 'ace'.
'ace' going around 'h' is 'ACHE'.
(Other definitions for ache that I've seen before include "strong feeling" , "suffering" , "Persistent dull pain" , "Long ? pain" , "Dull continuous pain" .)