simple vs linear

simple is a noun but linear is not a noun.

Word	Noun	Adjective	Verb	Adverb
simple	Yes	Yes	No	No
linear	No	Yes	No	No

simple (noun)	linear (noun)
a person lacking intelligence or common sense
any herbaceous plant having medicinal properties

simple (adjective)	linear (adjective)
(botany) of leaf shapes; of leaves having no divisions or subdivisions	of or in or along or relating to a line; involving or having a single dimension
having few parts; not complex or complicated or involved	designating or involving an equation whose terms are of the first degree
easy and not involved or complicated	of a circuit or device having an output that is proportional to the input
exhibiting childlike simplicity and credulity	measured lengthwise
unornamented	(of a leaf shape) long and narrow
lacking mental capacity and subtlety
apart from anything else; without additions or modifications