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

緩衝[kanshou] buffered
緩衝器[kanshouki] shock absorber
緩衝地帯[kanshouchitai] buffer zone
刺衝[shishou] stabbing
衝撃[shougeki] shock

衝撃波[shougekiha] shock wave
衝動[shoudou] impulse
衝動行為[shoudoukoui] shock action
衝動買い[shoudougai] impulsive buying
衝突[shoutotsu] collision