Forbidding experts with ugly expressions (8)
I believe the answer is:
grimaces
'ugly expressions' is the definition.
'grimaces' can be an answer for 'expressions' (I have seen 'Twisted expressions ' mean 'grimaces' so perhaps 'expressions' could also mean 'grimaces'). I'm unsure of the 'ugly' bit.
'forbidding experts' is the wordplay.
'forbidding' becomes 'grim' (I've seen this in another clue).
'experts' becomes 'aces' (ace is a kind of expert).
'grim'+'aces'='GRIMACES'
'with' is the link.
Can you help me to learn more?
(Other definitions for grimaces that I've seen before include "Contortion of face, perhaps expressing pain" , "threatening features" , "Makes wry expression" , "Facial distortions of distaste" , "Contorted facial expressions" .)