king vs Gustavus

king and Gustavus both are nouns.

Word	Noun	Adjective	Verb	Adverb
king	Yes	No	No	No
Gustavus	Yes	No	No	No

king (noun)	Gustavus (noun)
(chess) the weakest but the most important piece	king of Sweden who established Lutheranism as the state religion (1496-1560)
one of the four playing cards in a deck bearing the picture of a king	king of Sweden whose victories in battle made Sweden a European power; his domestic reforms made Sweden a modern state; in 1630 he intervened on the Protestant side of the Thirty Years' War and was killed in the battle of Lutzen (1594-1632)
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	king of Sweden who increased the royal power and waged an unpopular war against Russia (1746-1792)
a male sovereign; ruler of a kingdom	king of Sweden whose losses to Napoleon I led to his being deposed in 1809 (1778-1837)
a very wealthy or powerful businessman	king of Sweden who kept Sweden neutral during both World War I and II (1858-1950)
a male competitor who holds a preeminent position	the last king of Sweden to have any real political power (1882-1973)
the husband or widower of a queen
preeminence in a particular category or group or field