Unwary means not alert to possible danger or problems. An unwary hiker might wander off the trail without noticing warning signs about cliffs ahead. An unwary shopper might buy something that seems like a great deal without reading the fine print.

The word describes someone who isn't being cautious or watchful when they probably should be. It's not about being careless on purpose: unwary people simply aren't aware that something risky is happening. A student might be unwary of a trick question on a test, not realizing the teacher included a detail designed to catch people who read too quickly.

You'll often see this word in warnings: “Don't let unwary customers get fooled by fake reviews,” or “An unwary traveler might not realize that prices triple during tourist season.” The word suggests that paying closer attention would help someone avoid a problem. Being wary (the opposite) means staying alert and noticing potential issues before they become actual problems.