Learner's definition of PROFOUND. [more profound; most profound] 1. a : having or showing great knowledge or understanding. a profound thinker. His knowledge of history is profound. Her books offer profound insights into the true nature of courage. Computer technology has made profound [=major, significant] changes in our lives. His paintings have had a profound effect/impact/influence on her own work. [+] more examples [-] hide examples [+] Example sentences [-] Hide examples.