cool your jets

C

cool your jets (metaphor)
/kuːl jʊr dʒɛts/

Meanings

• To calm down and stop being angry, excited, or impatient.
• To slow down and avoid acting too quickly.
• To wait for a moment before speaking or taking action.

Synonyms: calm down; relax; take it easy; slow down; hold your horses; settle down.

Example Sentences

1. The coach told the frustrated player to cool your jets and focus on the next play instead of arguing with the referee.
2. When Daniel wanted to sign the contract immediately, his lawyer advised him to cool your jets and read the details carefully.
3. Sarah started complaining loudly about the delay, but her friend told her to cool your jets until they heard the official announcement.

Etymology and Origin

The idiom “cool your jets,” meaning to calm down or reduce one’s agitation, is widely associated with mid-20th-century American popular culture, particularly the era’s fascination with jet propulsion and space travel. During the late 1940s and early 1950s, rapid developments in aviation and rocketry captured public imagination, and aerospace terminology increasingly appeared in everyday speech as metaphorical language.

In this context, references to controlling engines or propulsion systems were easily adapted into figurative expressions. The phrase “cool your jets” evokes the idea of reducing the heat or intensity of jet engines, which metaphorically came to signify calming one’s emotions or slowing down impulsive behavior. Similar jet-related slang expressions circulated in science-fiction dialogue and youth-oriented adventure stories of the period, reflecting the broader cultural influence of aviation and early space-age enthusiasm.

Geographical Origin

The expression originated in the United States, where aviation technology and space-themed entertainment were particularly prominent after World War II. American science-fiction literature, radio, and early television programs frequently incorporated futuristic slang inspired by rocketry and jet propulsion. Within this cultural environment, expressions like “cool your jets” emerged as imaginative extensions of technical language into everyday speech.

Initial Printed Appearance

One of the earliest known printed examples appears in Stand by for Mars! (1952) by Carey Rockwell, the house pseudonym used for the Tom Corbett, Space Cadet series of novels. In the story, a character admonishes another during a tense moment:

“Cool your jets, space creep!”

Here the phrase is used idiomatically to tell someone to calm down, demonstrating that the figurative meaning was already established within the narrative dialogue.

Historical Development

The phrase gained wider recognition through the broader Tom Corbett, Space Cadet franchise, which included novels, radio programs, comic books, and a television series broadcast from 1950 to 1955. The franchise portrayed futuristic space-academy adventures and frequently employed imaginative slang influenced by aviation and rocketry. Such language helped reinforce the association between jet-engine imagery and emotional restraint.

As audiences encountered the expression through these popular media forms, the phrase gradually moved beyond science-fiction contexts into general colloquial use. By the later decades of the twentieth century, “cool your jets” had become a familiar American idiom used to advise someone to relax, slow down, or stop reacting angrily.

Variants

• cool it
• cool down
• keep your shirt on
• hold your horses

Anxious, Easy

Last update: March 9, 2026 12:48 AM