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

一縷[ichiru] a thread
縷説[rusetsu] detailed explanation
縷々[ruru] continuously
縷縷綿綿[rurumenmen] going on and on in tedious detail

一縷の望み[ichirunonozomi] gleam (ray) of hope
繁縷[hakobe] chickweed
繁縷塩[hakobejio] chickweed (stitchwort) roasted and mixed with salt, then ground into a powder for use as toothpaste