define adrenaline
or chiefly British adrenalin /ÉËdrÉnÉlÉn/. Learner's definition of ADRENALINE. [noncount]. : a substance that is released in the body of a person who is feeling a strong emotion (such as excitement, fear, or anger) and that causes the heart to beat faster and gives the person more energy. â If you experience a rush of adrenaline or an adrenaline rush, you feel very excited and full of energy. I felt a rush of adrenaline as I walked onto the stage. [+] more examples [-] hide examples [+] Example sentences [-] Hide examples. It was a thrilling experience that really got our adrenaline going.