Unthinking (adjective)

1. Acting without thinking or consideration.
2. Not conscious of the consequences or implications of one's actions.

Origin:

The word 'unthinking' is formed from the prefix 'un-' which means 'not' and the word 'thinking', which refers to the act of using the mind to consider or reflect on something. the adjective 'unthinking' was first used in the early 17th century.

Examples:

1. She made an unthinking remark that upset her friend.
2. His unthinking behavior caused him to lose his job.
3. An unthinking person might not realize the dangers of playing with fire.
4. He acted unthinkingly and damaged the painting.
5. An unthinking decision could lead to negative consequences.