neutron star vs pulsar

neutron star and pulsar both are nouns.

Word	Noun	Adjective	Verb	Adverb
neutron star	Yes	No	No	No
pulsar	Yes	No	No	No

As nouns, pulsar is a hyponym of neutron star; that is, pulsar is a word with a more specific, narrower meaning than neutron star:

neutron star: a star that has collapsed under its own gravity; it is composed of neutrons
pulsar: a degenerate neutron star; small and extremely dense; rotates very fast and emits regular pulses of polarized radiation

neutron star (noun)	pulsar (noun)
a star that has collapsed under its own gravity; it is composed of neutrons	a degenerate neutron star; small and extremely dense; rotates very fast and emits regular pulses of polarized radiation