Antonyms for the phrase "teaches lesson" could include words like "ignores," "neglects," "forgets," "overlooks," or "condones." These words imply a lack of action or attention on the part of the teacher or authority figure, rather than the active process of teaching that comes with teaching a lesson. If someone fails to teach a lesson, they may be seen as apathetic, lazy, or disinterested in the betterment of their students or those around them. On the other hand, actively teaching a lesson implies a desire to help others learn and grow, and shows a commitment to education and personal improvement.