All 4 Uses

adrenaline
in
American Sniper
(Auto-generated)

There was maximum adrenaline inside that tin can on treads.†
p. 156.8 *

adrenaline = “fight or flight” stimulating hormone
They were driven by more than just religion and adrenaline, even more than blood lust.†
p. 168.7
In battle, of course, I was fine—when your adrenaline is pumped, you don't feel anything.†
p. 217.9
It was a tremendous adrenaline rush—you're low and fast.†
p. 238.6

adrenaline rush = the intense feeling that comes from an increase in the "fight or flight" hormone

Definitions:

(1) (adrenaline)
“fight or flight” stimulating hormone secreted by the adrenal gland in response to stress (making the body feel excited and ready for action)

Doctors are more likely to use the term epinephrine (possibly shortened to epi or EP). Adrenalin as a proper noun without the ending "e" is a trademark name for the same chemical.
(2) (meaning too rare to warrant focus)