glad vs sad

glad is a noun but sad is not a noun.

Word	Noun	Adjective	Verb	Adverb
glad	Yes	Yes	No	No
sad	No	Yes	No	No

glad (noun)	sad (noun)
any of numerous plants of the genus Gladiolus native chiefly to tropical and South Africa having sword-shaped leaves and one-sided spikes of brightly colored funnel-shaped flowers; widely cultivated

glad (adjective)	sad (adjective)
showing or causing joy and pleasure; especially made happy	experiencing or showing sorrow or unhappiness
cheerful and bright	bad; unfortunate
feeling happy appreciation	of things that make you feel sad
eagerly disposed to act or to be of service