Self-employed? Initially good at nothing (3)
I believe the answer is:
ego
'self' is the definition.
(synonyms)
'employed? initially good at nothing' is the wordplay.
'initially' indicates taking the first letters.
'good' becomes 'g' (abbreviation).
'at' is a charade indicator (letters next to each other).
'nothing' becomes 'O' (looks like zero - 0).
The initial letter of 'employed' is 'e'.
'e'+'g'+'o'='EGO'
(Other definitions for ego that I've seen before include "Consciousness" , "One's sense of self-importance" , "Self-esteem, sense of self" , "(Person's) sense of self-esteem" , "See 21 Down" .)