Definition of "butt in" []

• To join a conversation or situation in which one is not welcome or invited; to interject (connotes a rude or discourteous interruption). (verb)
• To join a queue not at the end, but in the middle (verb)

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• "You need to let your hair down tonight and have a little fun, said Cara as she got into a semi-squat and popped her butt in and out to the rhythm."
• "After a swift, stomach-churning free fall she landed on her butt in a green, piss-warm stream."
• "As it slipped from my hand, I had to butt in the dark with my head -- I could hear the Morlock's skull ring -- to recover it."