caution; warning; attention

one day

a letter or character (symbol for a sound or a word) / (linguistics) script, writing system / (specific to Japanese) a written mora, a kana / writing in general, written words

a letter, a character (symbol for a sound or a word) / (linguistics) script, writing system / (specific to Japanese) a written mora, a kana / writing in general, written words

one, 1 / the first in order, foremost / the beginning / the best / a kind of; one of something / (card games) an ace / unity / the bottom string of a shamisen or other Japanese musical instrument

driving off a troublesome person, getting rid of a nuisance, good riddance

Same as above.

pay a bill

(colloquial) current boyfriend

careless, thoughtless, inattentive