乳幼児[nyuuyouji] infants
幼い[osanai] very young
幼馴染[osananajimi] childhood friend
幼魚[yougyo] fry (young fish)
幼形進化[youkeishinka] paedomorphosis

幼子[osanago] infant
幼児[youji] infant
幼児ポルノ[youjiporuno] child pornography
幼児語[youjigo] baby talk (like choo-choo for train, etc.)
幼時[youji] childhood

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