Below are possible answers for the crossword clue "Heads up!," e.g..
5 letter answer(s) to "heads up!," e.g.
ALERT
mentally perceptive and responsive;"an alert mind"; "alert to the problems"; "alive to what is going on"; "awake to the dangers of her situation"; "was now awake to the reality of his predicament"
a warning serves to make you more alert to danger
an automatic signal (usually a sound) warning of danger
condition of heightened watchfulness or preparation for action; "bombers were put on alert during the crisis"
engaged in or accustomed to close observation; "caught by a couple of alert cops"; "alert enough to spot the opportunity when it came"; "constantly alert and vigilant, like a sentinel on duty"
quick and energetic;
warn or arouse to a sense of danger or call to a state of preparedness; "The empty house alarmed him"; "We alerted the new neighbors to the high rate of burglaries"
Other crossword clues with similar answers to '"Heads up!," e.g.'