Spreading organism devours posh twit (9)
I believe the answer is:
ignoramus
'twit' is the definition.
The definition and answer can be both people as well as being singular nouns.
Maybe there's a link between them I don't understand?
'spreading organism devours posh' is the wordplay.
'spreading' indicates an anagram.
'devours' means one lot of letters goes inside another (inserted letters are devoured).
'posh' becomes 'u' (abbreviation for upper-class - opposite to non-U).
'organism' with letters rearranged gives 'ignorams'.
'ignorams' placed around 'u' is 'IGNORAMUS'.
Can you help me to learn more?
(Other definitions for ignoramus that I've seen before include "At the present time" , "Idiot" , "Ignorant person" , "unwitting person" , "Stupid person" .)