The phrase "on one's toes" refers to someone being alert, attentive, and ready to act quickly. Sometimes, it is necessary to vary our language and use different phrases with similar meaning. Here are some synonyms for the phrase "on one's toes": alert, awake, aware, cautious, vigilant, observant, watchful, ready, prepared, attentive, focused, sharp, quick-witted, nimble, responsive, agile, astute, perceptive, vigilant, vigilant, on the ball, sharp-eyed, eagle-eyed, and bright. Using these synonyms, we can communicate effectively and express ourselves more precisely to convey the meaning of being attentive and ready to act at all times.