If you describe someone as unwary, you mean that they are not cautious or experienced and are therefore likely to be harmed or deceived. With its quicksands the river usually drowns a few unwary visitors every season. The unwary are people who are unwary. Specialist subjects are full of pitfalls for the unwary
not alert to danger or deception; "the shrieks of unwary animals taken by surprise"; "some thieves prey especially on unwary travelers"; "seduce the unwary reader into easy acquiescence"- O J Campbell