big vs broad

big is not a noun while broad is a noun.

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

big (noun)	broad (noun)
	slang term for a woman

big (adjective)	broad (adjective)
above average in size or number or quantity or magnitude or extent	having great (or a certain) extent from one side to the other
conspicuous in position or importance	showing or characterized by broad-mindedness
given or giving freely	lacking subtlety; obvious
generous and understanding and tolerant	broad in scope or content
marked by intense physical force	not detailed or specific
significant	being at a peak or culminating point
prodigious	very large in expanse or scope
serious or severe	(of speech) heavily and noticeably regional
loud and firm
(of animals) fully developed
in an advanced stage of pregnancy
feeling self-importance
exhibiting self-importance