It originated in the 16th and 17th centuries, derived from the French word "honni soit qui mal y pense" (shame on whoever thinks ill of it).
This phrase was associated with the Order of the Garter, and translators were sometimes referred to as "honyacks" because they were seen as intermediaries who could bridge the gap between different cultures.
Today, the word "honyack" is rarely used. You might find it in historical texts, but it's not a common term in modern English.