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

一冊[issatsu] one copy (e.g. book)
冊子[sasshi] book
冊子[soushi] written work (esp. a bound text, as opposed to a scroll)
冊数[sassuu] number of books
冊立[sakuritsu] imperial investiture

数冊[suusatsu] several volumes (books)
短冊[tanzaku] long, narrow card on which Japanese poems are written (vertically)
分冊[bunsatsu] separate volume
別冊[bessatsu] separate volume