The difference between Approval and Consent

When used as nouns, approval means an expression granting permission, whereas consent means voluntary agreement or permission.

Consent is also verb with the meaning: to express willingness, to give permission.

check bellow for the other definitions of Approval and Consent

Approval as a noun:

An expression granting permission; an indication of agreement with a proposal; an acknowledgement that a person, thing or event meets requirements.

Examples:

"I need to get an approval on this purchase order."
Approval as a noun:

An expression of favorable acceptance and encouragement; a compliment that also condones.

Examples:

"Words of approval never seem to come from him."
Approval as a noun (especially, philately):

Something mailed by a seller to a collector to match his stated interests; he can approve of or return the item.

Consent as a verb:

To express willingness, to give permission.

Examples:

"After reflecting a little bit, I've consented."
Consent as a verb (medicine):

To cause to sign a consent form.
Consent as a verb (obsolete):

To grant; to allow; to assent to.
Consent as a verb:

To agree in opinion or sentiment; to be of the same mind; to accord; to concur.

Consent as a noun:

Voluntary agreement or permission.
Consent as a noun (obsolete):

Unity or agreement of opinion, sentiment, or inclination.
Consent as a noun (obsolete):

Advice; counsel.