Bully

A bully is someone who torments and taunts others, with the term most often associated with older children "picking on" younger ones, with this relationship common in siblings.

The immortal Flint once referred to his first life as Akharin, saying that he was "a soldier, a bully, and a fool". 

Captain Jean-Luc Picard once told his brother Robert that when they were growing up, Robert had been a bully. Robert responded that he had enjoyed bullying Jean-Luc with the statement resulting in the two having a fight. 

Jake Potts once bullied his brother Willie with deadly consequences. Jake tricked Willie into thinking Willie had killed him in a laser duel and Willie, in terror, fled into an alien forest on Ogus II and ate a deadly cove palm. Willie was later rushed to a starbase for emergency medical care. 

Captain Kathryn Janeway once told Maje Culluh of the Kazon-Nistrim that she didn't like threats or bullies, as she considered him to be a bully.