support vs back

support and back both are nouns.

Word	Noun	Adjective	Verb	Adverb
support	Yes	No	Yes	No
back	Yes	Yes	Yes	Yes

As nouns, back is a hyponym of support; that is, back is a word with a more specific, narrower meaning than support:

As verbs, back is a hyponym of support; that is, back is a word with a more specific, narrower meaning than support:

Other hyponyms of support include back up, vouch, verify, demonstrate, establish, prove, shew, show, document, validate.

As verbs, back is a hyponym of support; that is, back is a word with a more specific, narrower meaning than support:

As verbs, support and back are synonyms defined as:

Other synonyms of support include endorse, indorse, plump for, plunk for.

support (noun)	back (noun)
aiding the cause or policy or interests of	(American football) the position of a player on a football team who is stationed behind the line of scrimmage
the act of bearing the weight of or strengthening	the side that goes last or is not normally seen
documentary validation	a support that you can lean against while sitting
a military operation (often involving new supplies of men and materiel) to strengthen a military force or aid in the performance of its mission	the part of a garment that covers the back of your body
the activity of providing for or maintaining by supplying with money or necessities	the protective covering on the front, back, and spine of a book
any device that bears the weight of another thing	the posterior part of a human (or animal) body from the neck to the end of the spine
supporting structure that holds up or provides a foundation	the series of vertebrae forming the axis of the skeleton and protecting the spinal cord
something providing immaterial assistance to a person or cause or interest	the part of something that is furthest from the normal viewer
a musical part (vocal or instrumental) that supports or provides background for other musical parts	(football) a person who plays in the backfield
the financial means whereby one lives
financial resources provided to make some project possible

support (adjective)	back (adjective)
	related to or located at the back
	of an earlier date
	located at or near the back of an animal

support (verb)	back (verb)
establish or strengthen as with new evidence or facts	establish as valid or genuine
put up with something or somebody unpleasant	strengthen by providing with a back or backing
adopt as a belief	shift to a counterclockwise direction
argue or speak in defense of	place a bet on
be a regular customer or client of	travel backward
be the physical support of; carry the weight of	cause to travel backward
play a subordinate role to (another performer)	support financial backing for
support materially or financially	be behind; approve of
give moral or psychological support, aid, or courage to	give support or one's approval to
be behind; approve of	be in back of
support with evidence or authority or make more certain or confirm

support (adverb)	back (adverb)
	at or to or toward the back or rear
	in or to or toward a past time
	in repayment or retaliation
	in or to or toward a former location
	in or to or toward an original condition
	in reply