Put off initially, due entirely to extraordinary reception (5)
I believe the answer is:
deter
'put off' is the definition.
(both can mean to discourage)
'initially due entirely to extraordinary reception' is the wordplay.
'initially' suggests taking the first letters.
The initial letters of 'due entirely to extraordinary reception' is 'DETER'.
(Other definitions for deter that I've seen before include "Discourage or prevent from doing something" , "Put off (from an action)" , "Dishearten" , "Warn off" , "Try to prevent" .)