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

一癖[hitokuse] trait
飲酒癖[inshuheki] alcoholic addiction
奇癖[kiheki] strange habit
癖者[kusemono] ruffian
潔癖[keppeki] fastidiousness

口癖[kuchiguse] way of saying
習癖[shuuheki] (bad) habit
常用癖[jouyouheki] addiction
性癖[seiheki] disposition
盗癖[touheki] kleptomania