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

一眼[ichigan] one eye
一眼レフ[ichiganrefu] single-lens reflex camera
一隻眼[issekigan] sharp eye
遠眼[engan] farsightedness
遠眼鏡[toomegane] spectacles for far-sightedness

凹眼[ougan] cavernous eyes
凹眼鏡[ougankyou] concave glasses
開眼[kaigan] enlightenment
眼下[ganka] under one's eyes
眼科[ganka] ophthalmology