Man glowering admits it's of English extraction (5)
I believe the answer is:
anglo
'of english extraction' is the definition.
The definition suggests a singular noun which matches the answer.
'man glowering admits' is the wordplay.
'admits' says the answer is hidden in the clue.
'ANGLO' is hidden in the letters of 'man glowering'.
'it's' is the link.
Can you help me to learn more?
(Other definitions for anglo that I've seen before include "Prefix denoting English" , "Prefix meaning English or British" .)