The origin may likewise suggest "to be red." In this situation the small form chamor may have been originated from the reddish-brown skin of a specific kind of the ass. Below is a timeline revealing historical citations in Green's for the standard usage of "ass" as butt. To have (one's) direct (one's) butt "not recognize what one is doing" is proven by 1969. Colloquial (one's) butt "one's self, one's person" attested by 1958. To not understand one's ass from ___ "not know anything, be a fool," i...