ちょっと一杯[chottoippai] let's have a quick drink
ばつ一[batsuichi] being once divorced
一向[hitaburu] nothing but
サラダ一皿[saradahitosara] plate of salad

安全第一[anzendaiichi] safety first
一か八か[ichikabachika] sink or swim
一っ走り[hitoppashiri] spin (as in 'take a car for a spin')
一つ一つ[hitotsuhitotsu] one-by-one

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

一進一退[isshinittai] now advancing and now retreating
引退[intai] retire
隠退[intai] retirement
隠退生活[intaiseikatsu] secluded life
遠退く[toonoku] to become distant

遠退ける[toonokeru] to keep (someone) at a distance
押し退ける[oshinokeru] to push aside
撃退[gekitai] repulse
減退[gentai] decline
後退[koutai] retreat

ジェット推進研究所[jettosuishinkenkyuusho] Jet Propulsion Laboratory
一進一退[isshinittai] now advancing and now retreating
一歩前進[ippozenshin] (a) step forward
栄進[eishin] promotion
詠進[eishin] presentation of poem (to court)

仮進級[karishinkyuu] conditional promotion
勘進[kanshin] reporting after careful investigation
勧進[kanjin] temple solicitation
勧進元[kanjinmoto] backer
勧進帳[kanjinchou] temple solicitation book