Upsetter

Part of speech: noun

Definitions

1. An individual or item that incites disturbance or upheaval in a situation or environment
2. A person or thing that unexpectedly defeats a favored opponent or causes disorder
3. One who or that which disrupts expectations by overcoming the likely winner or disturbing order

Etymology: "Upsetter" is simply "upset" with the agent suffix "-er" attached, so it means one who upsets. The base verb "upset" has a long history of its own: it was formed in English from "up" and "set," in the sense of overturning something, and the verb's figurative sense of disturbing or overturning an expected outcome developed from that physical image of knocking something over. The noun describes the competitor who knocks over a favourite, most often in sport, where the expected winner loses to an outsider. Its literal core is still visible: the upsetter is the force that tips the established order over. Because the suffix is productive and transparent, the word needs little more explanation than its parts, and its meaning follows directly from the verb it grows out of.

Synonyms: disruptor, disturber