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

直向[hitamuki] earnest
安直[anchoku] inexpensive
一直[icchoku] lining out to first base
一直線[icchokusen] straight line
鉛直[enchoku] perpendicular

下駄直し[getanaoshi] repairing clogs
開き直る[hirakinaoru] to become defiant
気を取り直す[kiwotorinaosu] to completely rethink
急転直下[kyuutenchokka] suddenly and precipitately
居直る[inaoru] to sit up properly straight

兎や角言う[toyakakuiu] to say all kinds of things
まっ四角[masshikaku] square
アフリカの角[afurikanotsuno] horn of Africa
一角[ikkaku] corner
一角の人物[hitokadonojinbutsu] somebody (important)

一角獣[ikkakujuu] unicorn
烏犀角[usaikaku] black rhinoceros horn
鋭角[eikaku] acute angle
外角[gaikaku] outside corner
町角[machikado] street corner