Translation guide
How to express 'slacken' in Japanese, covering physical loosening, reducing speed or intensity, and becoming less strict.
To make something less tight, such as a rope, belt, or screw.
General verb for loosening something that is tight. Transitive (you loosen something).
I loosened my belt.
Please loosen the screw.
Intransitive: something becomes loose by itself.
My shoelaces came loose.
To let something go slack, like a rope or line, often intentionally.
I slackened the rope.
To slow down, decrease effort, or become less active.
Used metaphorically for reducing pace, effort, or strictness. Transitive.
To drop or reduce speed, often used with スピード or ペース.
Intransitive: for wind, rain, or force to slacken/diminish.
To slack off, cut corners, or not put in full effort. Often negative nuance.
To relax rules, discipline, or control.
Transitive: to relax regulations, restrictions, or discipline.
They slackened the regulations.
To ease or mitigate restrictions, tension, or pain. More formal.
They slackened the restrictions.
To be lenient, to go easy on someone. Often used for discipline or grading.
The teacher slackened the grading.
緩める (yurumeru) is transitive (you loosen something), while 緩む (yurumu) is intransitive (something becomes loose). Use を with 緩める and が with 緩む.
The English idiom 'slack off' (be lazy) is not directly translated with 緩める. Use 手を抜く (te o nuku) or サボる (saboru) instead.
I slackened the pace of work.
車はスピードを落とした。
The car slackened its speed.
風が弱まった。
The wind slackened.
彼は仕事で手を抜いている。
He is slackening off at work.