Harebrained (adjective)

1. Being foolish, impulsive or impractical in one's thinking or ideas.
2. Having or showing a lack of good sense or judgement.

Origin:

Compound word hare + brained, refers to being foolish, impulsive or impractical in one's thinking or ideas.

Examples:

1. His harebrained scheme was doomed to failure from the start.
2. The harebrained idea was to jump off the roof with an umbrella.
3. Harebrained is used to describe a person who is foolish, impulsive or impractical in one's thinking or ideas.
4. Harebrained schemes are often ill-conceived and unlikely to succeed.
5. Harebrained ideas are characterized by a lack of foresight, common sense or judgement.