御猪口[ochoko] small cup
片口鰯[katakuchiiwashi] Japanese anchovy (Engraulis japonica)
白口[shiroguchi] white croaker (Pennahia argentata)
悪たれ口[akutareguchi] abuse
悪口雑言[akkouzougon] all kinds of malicious gossip

異口同音[ikudouon] in concert
異口同音に[ikudouonni] in one voice
ひと口[hitokuchi] mouthful
一口商い[hitokuchiakinai] an immediate definite deal
一口同音[ikkudouon] reading in unison

お早うございます[ohayougozaimasu] good morning
一刻も早く[ikkokumohayaku] immediately
いち早く[ichihayaku] promptly
口早[kuchibaya] rapid talking
最早[mohaya] already

時期が早い[jikigahayai] before scheduled
時期尚早[jikishousou] premature
時機尚早[jikishousou] before its time
早手[hayate] gale
手早い[tebayai] nimble

逸速く[ichihayaku] promptly
音速[onsoku] speed of sound
加速[kasoku] acceleration
加速運動[kasokuundou] accelerated motion
加速度[kasokudo] acceleration

快速[kaisoku] high speed
快速電車[kaisokudensha] high-speed train
角速度[kakusokudo] angular velocity
急速[kyuusoku] rapid (e.g. progress)
減速[gensoku] deceleration