sofa vs tete-a-tete

sofa and tete-a-tete both are nouns.

Word	Noun	Adjective	Verb	Adverb
sofa	Yes	No	No	No
tete-a-tete	Yes	Yes	No	No

As nouns, tete-a-tete is a hyponym of sofa; that is, tete-a-tete is a word with a more specific, narrower meaning than sofa:

Other hyponyms of sofa include convertible, sofa bed, daybed, divan bed, divan, love seat, loveseat, vis-a-vis, settee, squab.

sofa (noun)	tete-a-tete (noun)
an upholstered seat for more than one person	small sofa that seats two people
	a private conversation between two people

sofa (adjective)	tete-a-tete (adjective)
	involving two persons; intimately private