Direct Opposites:
* Hinder: To make it difficult for someone to do something.
* Obstruct: To block or prevent something from happening.
* Impede: To slow down or make progress difficult.
* Harm: To cause damage or injury.
* Hurt: To cause pain or suffering.
Opposite in meaning:
* Ignore: To pay no attention to someone or something.
* Neglect: To fail to care for someone or something.
* Abandon: To leave someone or something behind.
* Betray: To be disloyal to someone or something.
Antonyms:
* Deny: To refuse to give something or to do something.
* Reject: To refuse to accept something or someone.
* Refuse: To say no to something.
The best opposite for "help" will depend on the specific situation.