n., Younger sibling or cousin of the same sex, as younger brother or male cousin of a male, or younger sister or female cousin of a female; sibling or cousin of the same sex of the junior line, whether older or younger.
Koʻu kaikaina, my younger sibling.
hoʻokaikainaCaus/sim.; To claim a kaikaina relationship; to act as a kaikaina, to address and treat as kaikaina, as from affection.
n., The younger of two brothers or two sisters; used by a brother when speaking of a brother, or a sister of a sister. But if a brother speaks of a sister, or a sister of a brother, it is kaikunane. The word applies to the younger of two or more persons of like sex and parentage.