On the lookout is a phrase that means to be vigilant and watchful for potential danger or opportunity. The crossword solutions for this term are ALERT (5 letters), CAUTIOUS (8 letters), and OPENEYED (8 letters). ALERT means to be ready to respond quickly to any situation, CAUTIOUS means to be careful and prudent in one's actions, and OPENEYED means to be observant and aware of one's surroundings. All three words describe the state of being on the lookout.