oblique vs diagonal

oblique and diagonal both are nouns.

Word	Noun	Adjective	Verb	Adverb
oblique	Yes	Yes	No	No
diagonal	Yes	Yes	No	No

oblique (noun)	diagonal (noun)
a diagonally arranged abdominal muscle on either side of the torso	a punctuation mark (/) used to separate related items of information
any grammatical case other than the nominative	an oblique line of squares of the same color on a checkerboard
	(mathematics) a set of entries in a square matrix running diagonally either from the upper left to lower right entry or running from the upper right to lower left entry
	a line or cut across a fabric that is not at right angles to a side of the fabric
	(geometry) a straight line connecting any two vertices of a polygon that are not adjacent

oblique (adjective)	diagonal (adjective)
slanting or inclined in direction or course or position--neither parallel nor perpendicular nor right-angled	having an oblique or slanted direction
indirect in departing from the accepted or proper way; misleading	connecting two nonadjacent corners of a plane figure or any two corners of a solid that are not in the same face