An accident waiting to happen is a dangerous situation that is certain to cause an accident or cause something to go wrong. This expression usually refers to negligence, carelessness, bad planning, wrong procedures, etc.
Although this idiom often refers to situations, a person who is habitually clumsy and careless in their actions might be referred to as ‘an accident waiting to happen.’
Origin
The idiom ‘an accident waiting to happen has been used since at least 1915. It became particularly popular during the 1980s and 1990s.
Sentence Examples
“The main stretch of road I use to get to work is an accident waiting to happen. There are no red lights at the intersection and the people drive like maniacs.”
“My uncle Davey is an accident waiting to happen. He’s always working on project in his garage and he pays no attention to safety. He gets hurt at least once a week.”
“Another trip to the emergency room! This kid is an accident waiting to happen.”
“Captain Boone, why did you ground Lieutenant Isaacs?” “Because she was an accident waiting to happen.” — JAG: Crossing the Line (1997)
“Don’t you have a chainsaw?” “Oh, are you kidding me? Those things are accidents waiting to happen.” — Northern Exposure: Hello, I Love You (1994