locust UK /ˈləʊ.kəst/US /ˈloʊ.kəst/noun 6verb 1forms 3 noun6 •Any of the grasshoppers, often polyphenic and usually swarming, in the family Acrididae that are very destructive to crops and other vegetation, especially migratory locusts (Locusta migratoria). •Any of various often leguminous trees and shrubs, especially of the genera Robinia and Gleditsia; locust tree. •A fruit or pod of a carob tree (Ceratonia siliqua).Among other articles, they brought with them a great quantity of locusts, which are a kind of pulse, sweet and pleasant to the palate, and in shape resembling French beans, but longer. — 1789 •A cicada. •(Hong-Kong, offensive) A mainlander. •(slang, no longer used) A dose of laudanum. verb1 •To come in a swarm.This Philip and the black-faced swarms of Spain, The hardest, cruellest people in the world, Come locusting upon us, eat us up, Confiscate lands, goods, money […] — 1875 formslocusted · locusting · locusts