/kos"teuhr mung'geuhr, -mong'-, kaw"steuhr-/ , Chiefly Brit.
n.
1. Also called coster . a hawker of fruit, vegetables, fish, etc.
v.i.
2. to sell fruit, vegetables, fish, etc., from a cart, barrow, or stall in the streets; coster.
[ 1505-15; earlier costerdmonger. See COSTARD, MONGER ]