accidentally-on-purpose
phrase

- to do something intentionally but pretend it happened by chance

(Cambridge Dictionary)

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The phrase accidentally-on-purpose could be described as an intentional oxymoron, a figure of speech in which seemingly opposite terms appear together. Being contradictory terms, "accidentally" and "on-purpose" would normally not be paired in an expression.

In this case, the phrase was not accidental. Instead it was done on purpose with a sense of irony and humour. Many people utilize oxymora as a form of humour. Celebrity artist Andy Warhol once said, "I am a deeply superficial person." And Mark Twain was quoted as saying, "It usually takes three weeks to prepare a good spontaneous speech."

Many oxymora are unintentional. Below are a few examples that one might hear or read without thinking about the contradiction:

- The course is designed for "advanced beginners."

- I need an "original copy" of that document.

- He's been in "poor health" for some time now.

- I'd like to have your "unbiased opinion."

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Practice OWAD in a conversation today, say something like:

"When building their house extension, they ACCIDENTALLY-ON-PURPOSE forgot to ask for permission."