The antonyms for the word "out-doing" include underachieving, falling behind, losing, and being outdone. Underachieving refers to not meeting the expected standards, while falling behind suggests a lack of progress or development. Losing means failing to succeed or being defeated, and being outdone means being surpassed or overshadowed by others. These antonyms represent the opposite of out-doing, which means exceeding expectations, achieving success, and performing better than others. It is important to understand the different antonyms for a word as they help expand our language skills and aid us in expressing ourselves more effectively.