Verbal
I know words. I have the best words."
- — The real Donald J. Trump
Not quite the stupid expression the finical draftsperson believes it to be, “verbal” means “in any words”, not just in spoken ones. (The word for that enunciated subset of all possible words, he will superciliously continue, is “orally”.)
“A verbal agreement”, that odious fellow will continue, “is therefore any kind of agreement, not just one arrived at through the exclusive media of ears, lips and tongues. An “oral agreement” is the expression for which you are asking, kind sir.”
“To have your bleeding lights punched out is the experience for which you are asking,” kind sir might be tempted to reply, but — for we cannot condone violence in these pages, however heartily asked-for — perhaps a fellow unlearned in the ways of the law will find solace in the fact that “verbally” means the same as “orally or in writing”, and, being rendered without flannel, is more picturesquely put.
As to whether one might have a non-verbal agreement, well, those learned in the craft of semaphore, naval flags or bodily gesticulation would tell you that you may.
See also
Plain English Anatomy™
Noun | Verb | Adjective | Adverb | Preposition | Conjunction | Latin | Germany | Flannel | Legal triplicate | Nominalisation | Murder your darlings