to march off in a line, file by file; to file off.-same as defilade.-any narrow passage or gorge in which troops can march only in a file, or with a narrow front; a long, narrow pass between hills, rocks, etc.-the act of defilading a fortress, or of raising the exterior works in order to protect the interior. see defilade.-to make foul or impure; to make filthy; to dirty; to befoul; to pollute.-to soil or sully; to tarnish, as reputation; to taint.-to injure in purity of character; to corrupt.-to corrupt the chastity of; to debauch; to violate.-to make ceremonially unclean; to pollute.