swear up and down(redirected from sworn up and down)
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swear up and down
To make a very serious, solemn pledge, especially that one is telling the truth. Janet has sworn up and down that she wasn't the one to betray me, and I believe her.
swear up and downAMERICAN
If someone swears up and down that something is true, they insist very strongly that they are telling you the truth. He swore up and down he was going to get the cash and bring it right back. I couldn't get it out of my head that maybe it was all part of his plan, although he swore up and down it wasn't. Note: The usual British expression is swear blind.