일취월장이 · 일취월장을
rapid progress, improving day by day
Example
그 선수의 실력이 요즘 일취월장하고 있어요.
That athlete's skills are improving by leaps and bounds these days.
Word parts
일 day+취 achieve+월 month+장 advance
Literally 'achieve something daily, advance monthly'.
Good to know
Here 일 means 'day', not 'one' — don't confuse it with the other 일- idioms.
Related words