In general, knaves get ahead! (7)
I believe the answer is:
jackson
'in general' is the definition.
Although both the answer and definition are singular nouns, I don't see how one could define the other.
'knaves get ahead' is the wordplay.
'knaves' becomes 'jacks' ('jack' can be a synonym of 'knave').
'get' is a charade indicator (letters next to each other).
'ahead' becomes 'on' (synonyms).
'jacks'+'on'='JACKSON'
Can you help me to learn more?
(Other definitions for jackson that I've seen before include "See 13" , "American hero" , "Mississippi capital and 7th US president" , "American painter, 1912-56" , "Seventh US president Andrew - actress turned politician Glenda - singers Michael and Janet etc" .)