jam vs impede

jam is a noun but impede is not a noun.

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

As verbs, jam and impede are synonyms defined as:

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

As verbs, impede is a hypernym of jam; that is, impede is a word with a broader meaning than jam:

Other hypernyms of jam include hinder.

jam (noun)	impede (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

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