amusement vs nightlife

amusement and nightlife both are nouns.

Word	Noun	Adjective	Verb	Adverb
amusement	Yes	No	No	No
nightlife	Yes	No	No	No

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

amusement: an activity that is diverting and that holds the attention
nightlife: the entertainment available to people seeking nighttime diversion

Other hyponyms of amusement include beguilement, distraction, edutainment, extravaganza, militainment, night life, show.

amusement (noun)	nightlife (noun)
an activity that is diverting and that holds the attention	the activity of people seeking nighttime diversion (as at the theater, a nightclub, etc.)
a feeling of delight at being entertained	the entertainment available to people seeking nighttime diversion