Definitions:
offer goods or services at a lower price than (a competitor)

cut or wear away the part below or under (something, especially a cliff)

weaken; undermine

strike (a ball) with backspin so that it bounces high on landing.

a space formed by the removal or absence of material from the lower part of something

the underside of a sirloin of beef.

a hairstyle in which the hair is shaved or cut very short on the sides or back of the head but left relatively long on top