Unwise means showing poor judgement. Not stupid exactly — a decision that will look bad later.
The word is measured and slightly formal, which makes it useful for criticising gently: an unwise remark, an unwise investment, it would be unwise to assume. Advisers and reports reach for it because it points at the decision rather than the person. It is milder than foolish and much milder than reckless. The adverb unwisely usually follows the verb, as in he unwisely agreed.
1adjectiveunwiseShowing poor judgement; not sensible.
“It would be unwise to sign anything today.”
Old English
unwīs — unwise, foolish, ignorant, uninformed, insane
Middle English
unwis
English, today
unwise
From Middle English unwis, from Old English unwīs (“unwise, foolish, ignorant, uninformed, insane”), equivalent to un- + wise. Cognate with Dutch onwijs (“unwise”), German unweise (“unwise”), Danish uvis (“unwise”), Swedish ovis (“unwise”), Icelandic óvís (“unwise”).
Etymology from Wiktionary, CC BY-SA