Outlaw a bachelor, a motherless man (3)

I believe the answer is:

ban

I'm a little stuck... Click here to teach me more about this clue!

'outlaw' is the definition.
(banning is a kind of outlawing)

'a bachelor a motherless man' is the wordplay.
'a bachelor' becomes 'BA' (the qualification: Bachelor of Arts).
'a motherless man' becomes 'n' (knight, a man in chess. I am not sure about the 'motherless' bit.).
'ba'+'n'='BAN'

Can you help me to learn more?

(Other definitions for ban that I've seen before include "Officially prohibit" , "Veto" , "Embargo" , "Bar, prohibition" , "Stop" .)

I've seen this clue in the Evening Standard.

Want a hint initially instead of a full solution? Install my app