Definition of go off

The expression "go off" has multiple meanings, and its origin is somewhat obscure, as it evolved through various senses and contexts over time. In general, however, the term "go off" is believed to derive from the Old English phrase "gan of," which meant "to spoil" or "to rot." The first recorded use of the term "go off" appeared in the early 16th century, in the sense of "explode" or "detonate" - specifically, in reference to firearms. By the 19th century, the term had also come to describe the spontaneous combustion of explosive substances such as gunpowder. The meaning of "go off" expanded in the late 19th century to refer to the expiration or spoilage of food items, such as dairy products or perishables that had passed their sell-by date. This usage persists to this day, with the idiomatic expression "it's gone off" commonly used to describe spoiled food. In contemporary colloquial English, however, "go off" is most often used to describe a sudden and intense emotional or psychological response - usually one that is negative or disruptive, such as "he went off on her" (meaning he became angry or verbally abusive). This usage originated in the middle of the 20th century, as a shortening of the expression "lose one's temper" (or "lose one's mind," in the current pidgin variation). Some researchers have suggested that "go off" also draws from the idiom "go off the deep end," which similarly implies a sudden and irrational loss of composure. In any case, the versatility and flexibility of the term "go off" have contributed to its enduring popularity - as well as its manifold, often contradictory senses - in modern English. Whether describing a stick of dynamite, a sour loaf of bread, or an outburst of anger, this ancient phrase remains a vivid and evocative way of conveying a wide range of meanings to this day.