IPA: /ˈspɜrnər/
KK: /spɜrnər/
A person who rejects or refuses something with disdain or contempt.
He was known as a spurner of conventional ideas, always challenging the status quo.
Spurner is formed from "spurn" (from Old English "spernan", meaning to kick away or reject) and "-er" (meaning a person who). A spurner is a person who kicks away or rejects something.
Think of someone who 'kicks away' ('spurn') something — the '-er' just means a person. A spurner is someone who rejects or dismisses.