Cold hooter? Monks wear this (4)
I believe the answer is:
cowl
'monks wear this' is the definition.
The definition suggests a singular noun which matches the answer.
'cold hooter?' is the wordplay.
'cold' becomes 'c' (eg on taps).
'hooter?' becomes 'owl' (owls hoot).
'c'+'owl'='COWL'
Can you help me to learn more?
(Other definitions for cowl that I've seen before include "Cover for monk or chimney" , "Hood-shaped covering" , "Monk's hooded habit" , "form of protection?" , "Monk's hood - chimney cover" .)