1.
negligence, carelessness, letting one's guard down
A state of being unprepared or inattentive, often leading to mistakes or danger.
油断していたら事故に遭った。
I had an accident because I let my guard down.
試合の最後まで油断するな。
Don't let your guard down until the end of the match.
油断大敵という言葉を忘れるな。
Don't forget the saying 'carelessness is the great enemy.'
油断大敵 is a common proverb meaning 'overconfidence is one's greatest enemy'
USAGE: 油断 is used as a noun, with する as a verb, or as a na-adjective (油断な).
COMMON PATTERNS:
- 油断する (to let one's guard down)
- 油断できない (can't let one's guard down)
- 油断も隙もない (extremely alert, not letting one's guard down for a moment)
PROVERB:
- 油断大敵 (Carelessness is one's greatest enemy) - A warning against overconfidence.
ETYMOLOGY: The word comes from Buddhist terminology, where 油 (oil) was used in lamps. If one neglected (断つ) to add oil, the lamp would go out.