IPA: /ˈæntiˌkɪŋ/
KK: /æntiˌkɪŋ/
A person who claims the title of king while opposing the current king or ruler.
The antiking rallied his supporters to challenge the throne.
Antiking is formed from "anti-" (meaning against) and "king" (from Old English "cyning", meaning ruler or monarch). The word describes someone who opposes or is against a king.
Think of someone who is 'against' ('anti-') a 'king' — that's what antiking means.