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

尽く[kotogotoku] altogether
為尽す[shitsukusu] to do everything possible
一網打尽[ichimoudajin] (a) big haul
権柄尽く[kenpeizuku] dictatorial
使い尽くす[tsukaitsukusu] to use up

至れり尽せり[itareritsukuseri] very polite
縦横無尽[juuoumujin] freely
出尽くす[detsukusu] to be all out
承知尽く[shouchizuku] acting on mutual agreement
尽かす[tsukasu] to use completely

１月[ichigatsu] January
ひと月[ichigetsu] one month
下弦の月[kagennotsuki] waning moon
何ヶ月[nankagetsu] how many months?
何月[nangatsu] what month

佳月[kagetsu] good month
か月[kagetsu] (number of) months
花鳥風月[kachoufuugetsu] beauties of nature
各月[kakugetsu] every month
隔月[kakugetsu] every second month