jam vs spot jam

jam is a noun but spot jam is not a noun.

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

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

Other hyponyms of jam include barrage jam, point jam, blanket jam.

jam (noun)	spot 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

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