slow-witted vs backward

slow-witted and backward both are adjectives.

Word	Noun	Adjective	Verb	Adverb
slow-witted	No	Yes	No	No
backward	No	Yes	No	Yes

As adjectives, slow-witted and backward are synonyms defined as:

Other synonyms of slow-witted include feebleminded, half-witted.

slow-witted (adjective)	backward (adjective)
retarded in intellectual development	directed or facing toward the back or rear
	(used of temperament or behavior) marked by a retiring nature
	retarded in intellectual development
	having made less than normal progress

slow-witted (adverb)	backward (adverb)
	in a manner or order or direction the reverse of normal
	in or to or toward a past time
	at or to or toward the back or rear