A slang proclamation of agreement or confirmation. It is normally verbalized as a stand-alone word when a slang is called for, similar to the use of "yup". A speaker will prefer "affirmatory" to "yup" when he or she does not want to pronounce the "p", which is more disruptive to breathing.
"Affirmatory" - Jason S.
Unintended use: "I say, with regard to your inquiry, affirmatory"