English erected sign incorporating extremely refined circles (7)
I believe the answer is:
engirds
'circles' is the definition.
I know nothing about this answer so I cannot judge whether this works.
'english erected sign incorporating extremely refined' is the wordplay.
'english' becomes 'E' (abbreviation as in OED).
'erected' says the letters should be written in reverse (in a down clue, letters go up).
'incorporating' means one lot of letters goes inside another.
'extremely' suggests removing the centre (only the extremes of the word are used).
'refined' with its centre taken out is 'rd'.
'sign' in reverse letter order is 'ngis'.
'ngis' going around 'rd' is 'ngirds'.
'e'+'ngirds'='ENGIRDS'
Can you help me to learn more?