GABA vs amino acid

GABA and amino acid both are nouns.

Word	Noun	Adjective	Verb	Adverb
GABA	Yes	No	No	No
amino acid	Yes	No	No	No

As nouns, amino acid is a hypernym of GABA; that is, amino acid is a word with a broader meaning than GABA:

GABA: an amino acid that is found in the central nervous system; acts as an inhibitory neurotransmitter
amino acid: organic compounds containing an amino group and a carboxylic acid group

Other hypernyms of GABA include aminoalkanoic acid, neurotransmitter.

GABA (noun)	amino acid (noun)
an amino acid that is found in the central nervous system; acts as an inhibitory neurotransmitter	organic compounds containing an amino group and a carboxylic acid group