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

御化け[obake] goblin
御化け屋敷[obakeyashiki] haunted house
胡麻化し[gomakashi] hanky-panky
イオン化[ionka] ionization
カスタム化[kasutamuka] customization

コンピュータ化[konpyuutaka] computerization
シアン化合物[shiankagoubutsu] cyanide
シアン化物[shiankabutsu] cyanide
スリム化[surimuka] thinning
パーソナル化[paasonaruka] personalization

陰極[inkyoku] cathode
陰極線[inkyokusen] cathode rays
陰極線管[inkyokusenkan] cathode-ray tube
危極[kikyoku] crisis
窮極[kyuukyoku] ultimate

究極目的[kyuukyokumokuteki] extreme purpose
極く[goku] quite
極み[kiwami] height
極めて[kiwamete] exceedingly
極悪[gokuaku] heinous