king vs business leader

king and business leader both are nouns.

Word	Noun	Adjective	Verb	Adverb
king	Yes	No	No	No
business leader	Yes	No	No	No

As nouns, king and business leader are synonyms defined as:

Other synonyms of king include baron, big businessman, magnate, mogul, power, top executive, tycoon.

king (noun)	business leader (noun)
(chess) the weakest but the most important piece	a very wealthy or powerful businessman
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