悪友[akuyuu] undesirable friend
畏友[iyuu] one's esteemed friend
益友[ekiyuu] good friend
学友[gakuyuu] school friend
級友[kyuuyuu] classmate

旧友[kyuuyuu] crony
血友病[ketsuyuubyou] haemophilia
交友[kouyuu] friend
交友関係[kouyuukankei] one's relationships
校友[kouyuu] schoolmate

仇討[adauchi] vengeance
かたき討ち[katakiuchi] vengeance
討つ[utsu] to shoot (at)
検討[kentou] consideration
検討委員会[kentouiinkai] investigative commission

再検討[saikentou] re-examination
剿討[soutou] cleaning up
相討ち[aiuchi] simultaneously striking one another (in kendo, etc.)
尊王討幕[sonnoutoubaku] reverence for the emperor and the overthrow of the shogunate
討ち破る[uchiyaburu] to break