left-slanting vs backhand

left-slanting is not a noun while backhand is a noun.

Word	Noun	Adjective	Verb	Adverb
left-slanting	No	Yes	No	No
backhand	Yes	Yes	Yes	No

As adjectives, left-slanting and backhand are synonyms defined as:

left-slanting and backhand: (of handwriting) having the letters slanting backward

left-slanting (noun)	backhand (noun)
	a return made with the back of the hand facing the direction of the stroke

left-slanting (adjective)	backhand (adjective)
(of handwriting) having the letters slanting backward	(of racket strokes) made across the body with back of hand facing direction of stroke
	(of handwriting) having the letters slanting backward

left-slanting (verb)	backhand (verb)
	hit a tennis ball backhand