"clever, alert," 1926, from warning cry "heads up!" (i.e. "look up!"). As a noun, "a notification, a warning," by 1988.
updated on October 10, 2017
英语词源词典收录了45867条英语词源词条，基本涵盖了全部常用英语词汇的起源、历史，是研究英语词汇或通过词源学英语的必备工具。