One wants to be so described (5)
I believe the answer is:
needy
'one' is the definition.
Both the answer and definition are adjectives. Perhaps they are linked in a way I don't understand?
'to be so described' is the wordplay.
'to be' becomes 'need' (needing is a kind of being).
'so described' becomes 'y' (I can't justify this - if you can you should believe this answer much more).
'need'+'y'='NEEDY'
'wants' acts as a link.
Can you help me to learn more?
(Other definitions for needy that I've seen before include "badly craving affection" , "penniless" , "Poor; wanting affection" , "Hard up" , "Necessitous" .)