byword
Synonym discussion
Sense: noun/1
In sense 1, byword is closest to synonym when we say something is a byword for corruption or delay, but the two words are not the same. Synonym usually belongs to language, while byword here means a person or thing that people strongly connect with a quality. Epitome and embodiment also suggest a striking example, often with a more literary tone and sometimes with praise. Byword is more often used when public talk has fixed a bad reputation in people's minds. Symbol is broader and can describe a sign, object, or image without the idea of repeated public association. A medal can be a symbol of courage, but a wasteful project can become a byword for incompetence.
Etymology
Byword comes from Old English byword, formed from by and word. It first referred to a familiar saying or proverb passed from speaker to speaker. From that older meaning, English later developed the sense of a name, person, or thing that becomes strongly linked with a quality because people keep mentioning it in the same way.