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

御見舞[omimai] calling on someone who is ill
御仕舞[oshimai] the end
仕舞った[shimatta] damn it!
独り舞台[hitoributai] performing solo (by oneself)
円舞[enbu] waltz

円舞曲[enbukyoku] waltz (composition)
演舞場[enbujou] theatre
仮装舞踏会[kasoubutoukai] masquerade ball
仮面舞踏会[kamenbutoukai] masquerade ball
歌舞妓[kabuki] kabuki