small vs big

small is a noun but big is not a noun.

Word	Noun	Adjective	Verb	Adverb
small	Yes	Yes	No	Yes
big	No	Yes	No	Yes

small (noun)	big (noun)
a garment size for a small person
the slender part of the back

small (adjective)	big (adjective)
limited or below average in number or quantity or magnitude or extent	above average in size or number or quantity or magnitude or extent
made to seem smaller or less (especially in worth)	conspicuous in position or importance
have fine or very small constituent particles	given or giving freely
low or inferior in station or quality	generous and understanding and tolerant
relatively moderate, limited, or small	marked by intense physical force
slight or limited; especially in degree or intensity or scope	significant
lowercase	prodigious
not large but sufficient in size or amount	serious or severe
(of a voice) faint	loud and firm
(of children and animals) young, immature	(of animals) fully developed
	in an advanced stage of pregnancy
	feeling self-importance
	exhibiting self-importance