It may be jutting an inch, perhaps (4)
I believe the answer is:
chin
'it may be jutting an' is the definition.
The definition suggests a singular noun which matches the answer.
'inch perhaps' is the wordplay.
'perhaps' indicates anagramming the letters.
'inch' anagrammed gives 'CHIN'.
Can you help me to learn more?
(Other definitions for chin that I've seen before include "Protruding part of lower jaw" , "Bottom part of jaw" , "Front of lower jaw" , "Facial feature" , "Prominent feature" .)