クスクス笑う[kusukusuwarau] to giggle
けらけら笑う[kerakerawarau] to cackle
げらげら笑う[geragerawarau] to guffaw
一笑[isshou] laugh
一笑に付す[isshounifusu] to laugh (someone) down

一顰一笑[ippinisshou] (a) mood
可笑しい[okashii] funny
含み笑い[fukumiwarai] suppressed laugh
嬉笑[kishou] happy laughter
戯笑[gishou] playful laughter

膝蓋骨[shitsugaikotsu] kneecap
膝蓋腱反射[shitsugaikenhansha] kneecap (patellar) reflex
膝関節[shitsukansetsu] knee joint
膝がしら[hizagashira] kneecap
片膝[katahiza] one knee

諸膝[morohiza] both knees
膝小僧[hizakozou] kneecap
膝許[hizamoto] near one's knee
膝行[shikkou] moving forward by sliding on one's knees (in the presence of high-ranking individuals)