: relating to, being, or causing physiological changes in the body (such as an increase in heart rate or dilation of bronchi) in response to stress
epinephrine is a fight-or-flight hormone
a fight-or-flight reaction

Examples of fight-or-flight in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Under stress, however, your body naturally shifts into the nervous system’s sympathetic or fight-or-flight mode, driving faster, shallower breaths from the upper chest. Dana Santas, CNN Money, 4 July 2025 The relationship puts me in a perpetual state of fight-or-flight. Lizz Schumer, People.com, 2 July 2025 What happens in your body when you’re stressed vs. anxious When you’re stressed, your body kicks into fight-or-flight mode. Lauryn Higgins, Time, 26 June 2025 In situations such as receiving critical feedback or navigating interpersonal conflict, the brain may default to a threat state, triggering physiological and cognitive responses akin to fight-or-flight. Andriana Eliadis, Forbes.com, 20 June 2025 See All Example Sentences for fight-or-flight

Word History

First Known Use

1973, in the meaning defined above

Time Traveler
The first known use of fight-or-flight was in 1973

Browse Nearby Words

Cite this Entry

“Fight-or-flight.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/fight-or-flight. Accessed 14 Jul. 2025.

Medical Definition

fight-or-flight

adjective
ˌfī-tər-ˈflīt
: relating to, being, or causing physiological changes in the body (such as an increase in heart rate or dilation of bronchi) in response to stress
the fight-or-flight response
Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!