Definitions by ridl

unbrother 

The step brother of your half sibling OR the half brother of your step sibling.

she married my unbrother, so I guess now she's my unsister-in-law

unbrother by ridl February 26, 2009

unsister 

The half sister of your half brother or half sister.

I got to see my unsister on Thanksgiving.

unsister by ridl February 26, 2009