main vs intense

main is a noun but intense is not a noun.

Word	Noun	Adjective	Verb	Adverb
main	Yes	Yes	No	No
intense	No	Yes	No	No

main (noun)	intense (noun)
a principal pipe in a system that distributes water or gas or electricity or that collects sewage
any very large body of (salt) water

main (adjective)	intense (adjective)
(of a clause) capable of standing syntactically alone as a complete sentence	possessing or displaying a distinctive feature to a heightened degree
most important element	(of color) having the highest saturation
of force; of the greatest possible intensity	extremely sharp or severe