くない

Etymology 1


. The kanji spellings appear to be.

This term appears to be rare, and it is not listed in many dictionaries.

Noun

 * 1)  a Japanese weapon, possibly derived from a masonry trowel

Etymology 2
Derived as a repurposing of the negative ending -ku nai of regular -i adjectives. Appears as slang in informal usage where standard Japanese would use instead.

Particle

 * 1)   isn't it, aren't you