One is unlikely to hear oneself so described (4)
I believe the answer is:
deaf
'described' is the definition.
Both the definition and answer are adjectives. Maybe they are linked in a way I don't understand?
'one is unlikely to hear oneself' is the wordplay.
I cannot really see how this works, but
'one' could be 'a' (a thing is one thing) and 'a' is found within the answer.
The remaining letters 'def' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
'so' is the link.
Can you help me to learn more?
(Other definitions for deaf that I've seen before include "Lacking hearing" , "Aurally challenged" , "Audibly challenged" , "Unable to hear" , "Not prepared to listen" .)