Assinine (or asinine) is a versatile expression which carries various meanings depending on the context in which it is applied. Although, most of the time it is used as a derogatory phrase.
The meanings of the word include: physically having the characteristics of a donkey, resembling buttocks, but usually it is said to someone who is not intelligent or somebody who is acting stupid.
The word originates from Latin language, with “asinus” being the root of the word, meaning “donkey”.
As a phrase, assinine was lifted into the English language somewhere around the mid-15th century.
The word asinine has been part of informal English language use since the 1600s.
Online, the phrase was part of a series of King of the Hill memes. One template was particularly popular, which featured a still of a serious Hank Hill with the caption: “That’s just asinine”.