"to throw into confusion," 1650s, from Latin consternatus, past participle of consternare "overcome, confuse, dismay, perplex, terrify, alarm," probably related to consternere "throw down, prostrate," from assimilated form of com-, here probably an intensive prefix (see com-), + sternere "to spread out, lay down, stretch out," from nasalized form of PIE root *stere- "to spread."
