If "implicate" means to suggest someone is involved in something:
* Exonerate: To clear someone of blame or suspicion.
* Acquit: To declare someone not guilty of a crime.
* Clear: To prove someone's innocence.
* Absolve: To free someone from guilt or responsibility.
If "implicate" means to show a connection between something:
* Disprove: To show something is false or incorrect.
* Refute: To argue against a statement or theory.
* Separate: To show that two things are not connected.
* Disconnect: To show that there is no link or relationship.
If "implicate" means to involve someone in something:
* Exclude: To keep someone out of something.
* Remove: To take someone out of a situation.
* Disassociate: To separate oneself from something.
The best antonym for "implicate" will depend on the specific context of the sentence.