Finding synonyms for the phrase "not possible" can come in handy when trying to express that something is impossible or cannot be done. Some popular synonyms to use in place of "not possible" include phrases such as "out of the question," "impractical," "unworkable," "infeasible," "insurmountable," and "unattainable." Other synonyms for this phrase include phrases like "unrealistic," "unachievable," "unfeasible," "not viable," and "unrealizable." When trying to convey the idea that something cannot be done, it's important to choose the right words to get your message across. Utilizing synonyms for "not possible" can help diversify your vocabulary and convey your message clearly to others.