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

御手玉[otedama] beanbag
御手上げ[oteage] all over
御手盛り[otemori] making arbitrary decisions which benefit oneself
御手洗い[otearai] toilet
お手伝いさん[otetsudaisan] maid

手子摺る[tekozuru] to have much trouble
引っ手繰り[hittakuri] purse snatching
悪手[akushu] poor move
握手[akushu] handshake
安手[yasude] cheap kind

意味深重[imishinchou] with profound (often hidden) meaning
一重ね[hitokasane] suit
一重継ぎ[hitoetsugi] sheep bend (knot)
一重桜[hitoezakura] cherry tree bearing single blossoms
荷重[kajuu] load

過重[kajuu] overweight
気が重い[kigaomoi] depressed
貴重[kichou] precious
貴重品[kichouhin] valuables
起重機[kijuuki] crane

あっとゆう間に[attoiumani] just like that
此間[konaida] the other day
此の間[konokan] the other day
間誤付かせる[magotsukaseru] to fluster
間誤付く[magotsuku] to be confused

クローン人間[kuroonningen] (human) clone
シゾイド人間[shizoidoningen] schizoid person
ベクトル空間[bekutorukuukan] vector space
π中間子[paichuukanshi] pi meson
位相空間[isoukuukan] phase space (physics)