undercut (under|cut)

verb

• 1offer goods or services at a lower price than (a competitor): these industries have been undercut by more efficient foreign producers

• 2cut or wear away the part below or under (something, especially a cliff): the base of the crag is undercut permitting walkers to pass behind the falling water
• cut away material to leave (a carved design) in relief.

• 3weaken; undermine: the chairman denied his authority was being undercut

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

noun

• 1a space formed by the removal or absence of material from the lower part of something: there may be some bigger fish in the safety of the undercut
• North American a notch cut in a tree trunk to guide its fall when felled.

• 2British the underside of a sirloin of beef.