hi-fi vs reproducer

hi-fi and reproducer both are nouns.

Word	Noun	Adjective	Verb	Adverb
hi-fi	Yes	Yes	No	No
reproducer	Yes	No	No	No

As nouns, reproducer is a hypernym of hi-fi; that is, reproducer is a word with a broader meaning than hi-fi:

hi-fi: equipment for the reproduction of sound with high fidelity
reproducer: an audio system that can reproduce and amplify signals to produce sound

hi-fi (noun)	reproducer (noun)
the reproduction of sound with little or no distortion	an audio system that can reproduce and amplify signals to produce sound
equipment for the reproduction of sound with high fidelity

hi-fi (adjective)	reproducer (adjective)
characterized by minimal distortion in sound reproduction