Is it farther or further?
"clever, alert," 1952, from warning cry "heads up!" (i.e. "look up!"), attested by 1939.
Clever; alert; shrewd: They're playing real heads-up football (1940s+)modifier
: Daschle was on Mitchell's heads-up list for good reasonnoun
A warning; a meeting where warning is given: blamed Young for not giving regents a ''heads up'' about the controversy/ Altman called a brief heads-up designed to tell the White House what procedures the RFC would follow (1990s+)