The company had to apply for an unsecured loan since it lacked collateral.

unsecured 是由前缀 un-（表示"无、不"）和动词 secure（担保、确保）的过去分词 secured 组合而成。unsecured 意思是"无担保的"，指不需要提供抵押物或担保人的贷款类型。