tough vs fibrous

tough is a noun but fibrous is not a noun.

Word	Noun	Adjective	Verb	Adverb
tough	Yes	Yes	No	No
fibrous	No	Yes	No	No

tough (noun)	fibrous (noun)
an aggressive and violent young criminal
a cruel and brutal fellow
someone who learned to fight in the streets rather than being formally trained in the sport of boxing

tough (adjective)	fibrous (adjective)
resistant to cutting or chewing	(of meat) full of sinews; especially impossible to chew
physically toughened	having or resembling fibers especially fibers used in making cordage such as those of jute
not given to gentleness or sentimentality
unfortunate or hard to bear
substantially made or constructed
feeling physical discomfort or pain (`tough' is occasionally used colloquially for `bad')
violent and lawless
very difficult; severely testing stamina or resolution
making great mental demands; hard to comprehend or solve or believe