The difference between Oppose and Prevent

When used as verbs, oppose means to attempt to stop the progression of, whereas prevent means to stop (an outcome).

check bellow for the other definitions of Oppose and Prevent

Oppose as a verb:

To attempt to stop the progression of; to resist or antagonize by physical means, or by arguments, etc.; to contend against; to confront; to resist; to withstand.

Examples:

"to oppose the king in battle; to oppose a bill in Congress"

"There is still time to oppose this plan."
Oppose as a verb:

To object to.

Examples:

"Many religious leaders oppose cloning humans."
Oppose as a verb:

To present or set up in opposition; to pose.

Examples:

"They are opposed to any form of hierarchy."
Oppose as a verb:

To place in front of, or over against; to set opposite; to exhibit.

Prevent as a verb (transitive):

To stop (an outcome); to keep from (doing something).

Examples:

"I brush my teeth regularly to prevent them from turning yellow."
Prevent as a verb (intransitive, now, rare):

To take preventative measures.
Prevent as a verb (obsolete, transitive):

To come before; to precede.
Prevent as a verb (obsolete, transitive):

To outdo, surpass.
Prevent as a verb (obsolete, transitive):

To be beforehand with; to anticipate.