unthinking

American  

[uhn-thing-king] / ʌnˈθɪŋ kɪŋ /

adjective

1. thoughtless; heedless; inconsiderate.

   an unthinking, tactless person.

2. indicating lack of thought or reflection.

   a dull, unthinking expression on his face.

3. not endowed with the faculty of thought.

   unthinking matter.

4. not exercising thought; not given to reflection.

   This book will not profit an unthinking person.

5. not thinking; unmindful.

   chores done in an unthinking manner.

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unthinking British  

/ ʌnˈθɪŋkɪŋ /

adjective

1. lacking thoughtfulness; inconsiderate

2. heedless; inadvertent

   it was done in an unthinking moment

3. not thinking or able to think

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Other Word Forms

• unthinkingly
  adverb
• unthinkingness
  noun

Etymology

Origin of unthinking

First recorded in 1670–80; un- ¹ + thinking

Explanation

Something that's unthinking is done without carefully considering how it might affect other people. An unthinking comment about your best friend's haircut might really hurt her feelings. If you do something in an unthinking way, it's automatic or impulsive. Your unthinking prejudice against a certain breed of dog, for example, might be undermined when you actually meet a sweet Doberman. And your unthinking run through your Dad's flower garden to catch a football may instantly fill you with regret: if you'd stopped and thought about it, you wouldn't have done it.

Example Sentences

Much of this squares with Mencken’s character portrait of the “booboisie,” the unthinking type of American whose numbers seem to have exploded in recent decades, perhaps in interaction with contemporary historical events.

From Salon • Mar. 28, 2026

And that in turn prevents you from aimless or unthinking financial behavior.

From MarketWatch • Dec. 24, 2025

For all its promise, AI risks instilling in students an unthinking yet false understanding of themselves and society, destroying the morals and habits that make human flourishing possible.

From The Wall Street Journal • Dec. 14, 2025

Mr Harvey admitted sending them a letter in April 2017 which he now acknowledged was “crass, inappropriate… unthinking and insensitive”.

From BBC • Nov. 30, 2024

Phineas just walked serenely on, or rather flowed on, rolling forward in his white sneakers with such unthinking unity of movement that “walk” didn’t describe it.

From "A Separate Peace" by John Knowles