hǎo​bù

not at all

好不 hǎo​bù
not at all adjective
not at all; not in the least (often used in rhetorical constructions or before certain adjectives to express negation)

What you said is quite unreasonable.

very adjective
how very; extremely (used as an intensifier before a two-syllable adjective)

This family was very happy to be reunited after a long separation.

Frequency

Movie subtitles
2.24 per million appears in 1% of films

Sources

Definitions
CC-CEDICT
Frequency data
SUBTLEX-CH