to rely heavily on

kill two birds with one stone, do one task and finish two or more goals (literally, “one stone, two birds”)

(obsolete) being surprised twice / (obsolete) more specifically, describes the appearance of a woman who has a beautiful figure from behind but has an ugly face

Alternative form of 一々

all at once

once; one time

(rare) the first day of the month

one defeat

first, foremost, number one

one person / singleness, singularity / one's own efforts or strengths / an unmarried person, single