noun

a person who habitually seeks to harm or intimidate those whom they perceive as vulnerable.

he is a ranting, domineering bully

persecutor,oppressor,tyrant,tormentor,browbeater,intimidator,coercer,subjugator,scourge,tough,heavy,bully boy,ruffian,thug,attack dog,badass

verb

seek to harm, intimidate, or coerce (someone perceived as vulnerable).

her 11- year-old son has been constantly bullied at school

persecute,oppress,tyrannize,torment,browbeat,intimidate,cow,coerce,strong-arm,subjugate,domineer,push about,push around,play the heavy with,pressure,pressurize,bring pressure to bear on,use pressure on,put pressure on,constrain,lean on,press,push,force,compel,oblige,put under an obligation,hound,harass,nag,harry,badger,goad,prod,pester,brainwash,bludgeon,persuade,prevail on,work on,act on,influence,dragoon,twist someone’s arm,blackjack,bulldoze,railroad,put the screws/squeeze on,bounce,hustle,fast-talk