POLITICAL or RELIGIOUS organization.' and the opposite word of 'Secede' is 'Unite'.Example: The kingdom of Belgium SECEDED from the Netherlands in 1830.Hence the correct opposite word is Unite.WORDSMEANINGQuit(verb)leave (a place), usually permanently.Resign(verb)VOLUNTARILY leave a job or other position.Withdraw(verb)remove or TAKE away (something) from a particular place or position.