Adrenalin is a substance which your body produces when you are angry, scared, or excited. It makes your heart beat faster and gives you more energy. Seeing the crowd really got my adrenalin pumping. a chemical produced by your body when you are afraid, angry, or excited, which makes your heart beat faster (adrenal (19-21 centuries), from renal; because adrenaline is produced by the adrenal glands)