king vs world-beater

king and world-beater both are nouns.

Word	Noun	Adjective	Verb	Adverb
king	Yes	No	No	No
world-beater	Yes	No	No	No

As nouns, world-beater is a hypernym of king; that is, world-beater is a word with a broader meaning than king:

Other hypernyms of king include adult female, woman.

king (noun)	world-beater (noun)
(chess) the weakest but the most important piece	a competitor who holds a preeminent position
one of the four playing cards in a deck bearing the picture of a king
a checker that has been moved to the opponent's first row where it is promoted to a piece that is free to move either forward or backward
a male sovereign; ruler of a kingdom
a very wealthy or powerful businessman
a male competitor who holds a preeminent position
the husband or widower of a queen
preeminence in a particular category or group or field