最も[mottomo] most
最愛[saiai] beloved
最悪[saiaku] the worst
最下位のビット[saikainobitto] least significant bit
最外[saigai] outer-most

最寄[moyori] nearest
最期[saigo] one's last moment
最強[saikyou] strongest
最近[saikin] most recent
最恵国待遇[saikeikokutaiguu] most favored nation

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