IPA: /ʌnˈwaɪz/
KK: /ʌnˈwaɪz/
Not showing good judgment or sense; making poor choices.
It was unwise to invest all his savings in a single stock.
Unwise → It is formed from "un-" (meaning not) and "wise" (from Old English "wīs", meaning knowledgeable or prudent). The word "unwise" means not knowledgeable or lacking wisdom.
Think of 'not' ('un-') being added to 'wise', which means knowledgeable. This helps you remember that 'unwise' describes someone who is not knowledgeable or lacks wisdom.