They get very little money from a poet (7)

'they' is the definition.
Although both the answer and definition are nouns, they are not in the same form of the noun.

'very little money from a poet' is the wordplay.
'very little money' becomes 'sou' (sou can mean a small amount of money).
'from' means one lot of letters go next to another.
'a poet' becomes 'they' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'sou'+'they'='SOUTHEY'

'get' is the link.

Can you help me to learn more?