Expressions (phrases, clauses, etc.), Suru verb - included
to throw away as useless; to scrap
一族が苦労して積み上げてきたものを、お前は一瞬で反故にするつもりか。Do you intend to throw away in one instant what our family has painstakingly built up? to make null and void; to renege; to annul; to revoke
Also written 反古にする【ほごにする】