When we are asked to "be on the lookout for" something, it means we need to keep an eye out for it - to stay alert and watchful so we don't miss it. To avoid repetition of the phrase, we can use synonyms such as "keep a lookout", "watch out for", "be vigilant for", "be alert for", "keep an eye out for", or "stay on the alert for". All of these phrases convey the same meaning as "be on the lookout for", but help to make our language more varied and interesting. So, next time you are tasked with being vigilant or watchful, try using one of these synonyms!