tad vs small indefinite amount

tad and small indefinite amount both are nouns.

Word	Noun	Adjective	Verb	Adverb
tad	Yes	No	No	No
small indefinite amount	Yes	No	No	No

As nouns, small indefinite amount is a hypernym of tad; that is, small indefinite amount is a word with a broader meaning than tad:

tad: a slight amount or degree of difference
small indefinite amount: an indefinite quantity that is below average size or magnitude

Other hypernyms of tad include small indefinite quantity.

tad (noun)	small indefinite amount (noun)
a slight amount or degree of difference	an indefinite quantity that is below average size or magnitude