tipster(n = noun.person) tout - one who sells advice about gambling or speculation (especially at the racetrack);
is a kind of adviser, advisor, consultant
has particulars: racetrack tout
Derived form noun tip3
One who makes a practice of giving or selling tips, or private hints or information, esp. for use in gambling upon the probable outcome of events, as horse races. [Webster 1913 Suppl.]
tipster, n. a person who gives tips, esp. about betting at horse-races.