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

隈無く[kumanaku] all over
然り気無い[sarigenai] nonchalant
だらし無い[darashinai] slovenly
途轍も無い[totetsumonai] extravagant
とんでも無い[tondemonai] unthinkable

無け無し[nakenashi] very small amount which looks like nothing
無駄にする[mudanisuru] to render futile
悪虐無道[akugyakubudou] treacherous
意気地無し[ikujinashi] coward
一も二も無く[ichimonimonaku] unhesitatingly