Unwary (adjective)

Not wary or not cautious or alert.

Origin:

From un- (not) + wary (cautious or alert).

Examples:

1. The unwary traveler was robbed.
2. The unwary person was caught off guard.
3. The unwary animal was caught in a trap.
4. The unwary fisherman was not prepared for the storm.
5. The unwary investor lost money.