Crossword clues for the word: ALERTER The word ALERTER has appeared as an answer to at least 9 crossword clues on different crossword puzzles. Crossword clues for ALERTER Showing 1 to 9 of 9 results Clue(s) Less sleepy More attentive More observant More on guard. More vigilant More watchful. One warning Siren say Tornado siren, e.g.