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

一騎[ikki] one horseman
一騎当千[ikkitousen] being a match for a thousand
騎行[kikou] horseback riding
騎士[kishi] knight
騎士道[kishidou] chivalry

騎射[kisha] shooting on horseback
騎手[kishu] horseman
騎乗[kijou] mount
騎馬[kiba] horse-riding
騎馬戦[kibasen] cavalry battle