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

ミドル級[midorukyuu] middleweight class
一級[ikkyuu] one grade
下級[kakyuu] lower grade
下級職[kakyuushoku] subordinate post
下級審[kakyuushin] lower court

下級生[kakyuusei] underclassmen
下層階級[kasoukaikyuu] proletariat
仮進級[karishinkyuu] conditional promotion
階級[kaikyuu] (social) class
階級章[kaikyuushou] rank insignia