一も二も無く[ichimonimonaku] unhesitatingly
一言二言[hitokotofutakoto] a word or two
一石二鳥[issekinichou] killing two birds with one stone
一二に及ばず[ichininioyobazu] right away
一姫二太郎[ichihimenitarou] It's good to have a girl first and then a boy

うり二つ[urifutatsu] as alike as two melons (two peas in a pod)
黄道十二宮[koudoujuunikyuu] twelve signs of the zodiac
二度[futatabi] again
最小二乗法[saishounijouhou] least-squares method
三十二分音符[sanjuunibuonpu] 32nd note

ミドル級[midorukyuu] middleweight class
一級[ikkyuu] one grade
下級[kakyuu] lower grade
下級職[kakyuushoku] subordinate post
下級審[kakyuushin] lower court

下級生[kakyuusei] underclassmen
下層階級[kasoukaikyuu] proletariat
仮進級[karishinkyuu] conditional promotion
階級[kaikyuu] (social) class
階級章[kaikyuushou] rank insignia

御神酒[omiki] sacred wine or sake
シェリー酒[sheriishu] sherry
三鞭酒[shanpen] champagne
麦酒[bakushu] beer
悪酒[akushu] cheap liquor

安酒[yasuzake] cheap sake
安酒場[yasusakaba] cheap saloon
飲酒[inshu] drinking alcohol (sake)
飲酒運転[inshuunten] drunken driving
飲酒癖[inshuheki] alcoholic addiction