To make a strong objection.
How dare you, I protest!
To affirm (something).
I do protest and declare …
To object to.
They protested the demolition of the school.
To call as a witness in affirming or denying, or to prove an affirmation; to appeal to.
To make a solemn written declaration, in due form, on behalf of the holder, against all parties liable for any loss or damage to be sustained by non-acceptance or non-payment of (a bill or note). This should be made by a notary public, whose seal it is the usual practice to affix.
To publish; to make known.