Similar to asking one to swear by something, this word is used in response to a statement that one suspects may not be true, or is very hard to believe.
"I just passed my driving test"

"You sweardown?"

"yes bruv!"
by zizu786 March 18, 2010

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Top Definition
A statement made to signify that what you speak is 100% the truth, the whole truth and nothing but the truth. Usually used when someone doesn't believe what you say, as it is bullshit, but this is used to try and make that person believe its true as its probably not.

What it actually means may derive from the old saying of "I swear on my mum's life!" which means absolutely nothing but some people think if that statement is said that they can't be lying.
"I swear down your honour, i didn't do it"

Nick: Did you know that Ahmed got arrested last night?
Keane: No he didn't.
Nick: Yeah man, swear down.
by GF November 30, 2006

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originating from chavs and pikeys in Ashford, UK.

Means to promise greatly to do something
i swear down I'm gona kill ya
by Ryk Turner January 22, 2005

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A phrase used to imply that one is telling the truth.
That gash is bare buff yeah. She was all over me n tingz swear down.
by Alvin Monero February 07, 2008

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meaning that you are being very honest about something.
todd -"A' fuckin Swear Down right, shut the fuck up, ya doin ma head in."
by fresh prince of bellend April 14, 2009

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