一つ返事

ひとつへんじ

ready reply, quick answer

一事

いちじ

one thing

一つ一つ

ひとつひとつ

one-by-one, separately, in detail

一大事

いちだいじ

serious affair

一仕事

ひとしごと いちしごと

task, (doing a) bit of work

一事が万事

いちじがばんじ

a single instance indicates what happens all the time, one case gives you an idea of what always happens

一つ

ひとつ

one

家事一切

かじいっさい

all the domestic (housekeeping) chores

世事一切

せじいっさい

all the worldly matters

仕事一筋

しごとひとすじ

living only for one's work, a life with no other interest than one's work

一朝有事

いっちょうゆうじ

(when) the time of need arises, should an emergency occur

仕事一途

しごといちず

singlemindedly devoted to work

一つまた一つ

ひとつまたひとつ

one by one; one after another

一つずつ

ひとつずつ ひとつづつ

one by one, one each, one at a time

一つ二つ

ひとつふたつ

one or two, a few, small number

一つ穴

ひとつあな

same hole (in which to live)

一つ釜

ひとつかま

one or the same pot, eating or living together

身一つ

みひとつ

one's body alone, lacking possessions

何一つ

なにひとつ

(not) one (usu. in neg. phrases)