impede vs jam

impede is not a noun while jam is a noun.

Word	Noun	Adjective	Verb	Adverb
impede	No	No	Yes	No
jam	Yes	No	Yes	No

As verbs, impede and jam are synonyms defined as:

Other synonyms of impede include block, close up, obstruct, obturate, occlude.

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

impede (noun)	jam (noun)
	deliberate radiation or reflection of electromagnetic energy for the purpose of disrupting enemy use of electronic devices or systems
	preserve of crushed fruit
	a dense crowd of people
	informal terms for a difficult situation

impede (verb)	jam (verb)
block passage through	interfere with or prevent the reception of signals
be a hindrance or obstacle to	crowd or pack to capacity
	get stuck and immobilized
	block passage through
	crush or bruise
	press tightly together or cram
	push down forcibly