the.com/adrenaline rush

means A sudden surge of energy, heightened alertness, and physical arousal triggered by a burst of adrenaline in response to excitement, fear, or danger.

from Adrenaline (the hormone) was named in the late 1800s by combining Latin 'ad-' (toward/near) and 'ren' (kidney), since the adrenal glands sit atop the kidneys — literally 'the thing near the kidney.' 'Rush,' meaning a sudden forceful flow, comes from Old French 'ruser' or Middle English 'ruschen,' describing anything that surges fast and hard. Put together, the phrase is 20th-century, born once scientists understood that fear or excitement floods the body with this kidney-adjacent hormone all at once — language catching up to physiology.