Mutual agreement is consent.understanding (n.)
Old English understanding "comprehension," verbal noun from understand (v.). Meaning "mutual agreement" is attested from 1803.
Also interesting to note that understanding is a verb when written but a noun when spoken.
(The previous statement sould be viewed as inaccurate)
What other words are there that change their nature when delivered verbally? Indeed when the definition of verbal is examined I find no reference to oral or spoken words. Instead verbal as an ADJECTIVE makes reference to the following:
A verbal noun is a noun derived from a verb and sharing in its senses and constructions.
Adjectives are used to:
adjective (n.)
"word used to qualify, limit, or define a noun or noun-like part of speech,"
My opening premise was not accurate. Verbal does not have anything to do with oral or spoken presentation. My bad. I would suggest you not present verbal arguments because any action that modifies a noun is deceitful and dishonorable. Nouns are not modified.