swear blind

(redirected from swear up and down and blue)

swear blind

To make a very serious, solemn pledge, especially that one is telling the truth. Janet has sworn blind that she wasn't the one to betray me, and I believe her.
See also: blind, swear

swear blind

BRITISH or

swear up and down

AMERICAN
If someone swears blind that something is true, they insist that they are telling you the truth. He swore blind that he hadn't taken the money. He swears blind that he bears no grudges against Manchester United for sacking him, but I don't know if I believe him.
See also: blind, swear

swear blind

affirm something in an emphatic manner. British informal
A North American variant of this expression is swear up and down .
See also: blind, swear