/ əˈdrenəlɪn; NAmE / noun
[ U ] a substance produced in the body when you are excited, afraid or angry. It makes the heart beat faster and increases your energy and ability to move quickly :
The excitement at the start of a race can really get the adrenalin flowing .
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WORD ORIGIN
early 20th cent.: from adrenal (see adrenal gland ) + -in , forming names of organic compounds.