緩々[yuruyuru] very loose
緩い[nukui] lukewarm
緩い[yurui] loose
緩み[yurumi] slack
緩む[yurumu] to become loose

緩める[yurumeru] to loosen
緩やか[yuruyaka] loose
緩下薬[kangeyaku] laxative
緩急[kankyuu] pace
緩行[kankou] going slowly

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