am·bi·tious [am bísh?ss] adjective 1. having strong desire for success: having a strong desire to be successful in life 2. needing great effort to succeed: sounding impressive but difficult to achieve because very high standards have been set or a great deal of work is required an ambitious plan to increase market share 3. strongly desirous: with a strong desire to have or do something ambitious to be the youngest person ever to win the championship -am·bi·tious·ly, adverb -am·bi·tious·ness, noun