He sold fake insurance policies to unwary customers. 他向未提防的顾客出售假保险。
A range of tax and technical issues can trip up the unwary (= unwary people). 一系列的税务和技术问题会使粗心大意的人出错。
Synonym: unsuspecting
Opposites: leery suspicious (DOUBT)wary
Compare: gulliblenaive