To hector is to boss around or verbally bully someone. An older brother might hector his little sister until she hands over part of her Halloween candy.
When you bombard someone with words, nagging and badgering until you get what you want, you hector. A teacher might feel the need to hector a class that consistently forgets to hand in homework assignments, and a playground bully might hector another child to give him her lunch money. The verb hector comes from the character in Greek mythology — Hector — who rallied the Trojans to keep fighting.