psychology, scientific discipline that studies mental states and processes and behaviour in humans and other animals. The discipline of psychology is broadly divisible into two parts: a large profession of practitioners and a smaller but growing science of mind, brain, and social behaviour. Learn the meaning and usage of the adjective psychological, which relates to psychology, the mind, or emotions. Find synonyms, antonyms, translations, and related words for psychological. The meaning of PSYCHOLOGICAL is of or relating to psychology. How to use psychological in a sentence. You may be surprised by how relevant psychology is in your everyday life. Read on to learn basic psychology facts, from the branches of psychology to career paths.