Unwise (adjective)

Not having good judgement or showing poor judgement in making decisions or acting.

Origin:

Derived from the old english word 'wīs' which means wise or knowledgeable.

Examples:

1. It was unwise to invest all of her savings in that risky stock.
2. It was unwise to trust the salesman's false promises.
3. It was unwise to ignore the weather forecast and go on the hike in the storm.
4. It was unwise to drive after drinking so much alcohol.
5. It was unwise to talk back to the boss and risk getting fired.