autodefenderse

To defend oneself, whether physically (in an altercation) or verbally/legally (against an accusation): se autodefendió sin ayuda de un abogado. Emphasizes acting without outside help — a lawyer, a bodyguard — more than plain defenderse does.

• Decidió autodefenderse en el juicio sin contratar a un abogado. — He decided to defend himself in the trial without hiring a lawyer.
• Aprendió artes marciales para poder autodefenderse. — She learned martial arts to be able to defend herself.
• El acusado se autodefendió con argumentos sólidos. — The accused defended himself with solid arguments.

Treating autodefenderse as identical to defenderse in every context — autodefenderse specifically foregrounds acting without professional or outside help, which matters most in legal contexts (representing yourself in court).

Often confused with defender.