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

庵室[anshitsu] hermit's cell
暗室[anshitsu] dark room
医務室[imushitsu] doctor's office
育児室[ikujishitsu] nursery
一室[isshitsu] one room

閲覧室[etsuranshitsu] inspection room
応接室[ousetsushitsu] drawing room
王室[oushitsu] royal family
温室[onshitsu] greenhouse
化粧室[keshoushitsu] toilet