Sentence:  Though the rebels had utterly failed in their purposes, having accomplished nothing but the temporary disabling of two lightly armed vessels, and had retreated before the approach of the only formidable vessel there, they formally, and with a <WSD>mendacity</WSD> equalled only by some of their own efforts in that direction, proclaimed that they had "driven out of sight, for a time, the entire hostile fleet," and that the blockade of the port of Charleston was raised. 
Meaning of the word marked with <WSD> tags:  A deceit, falsehood, or lie.