The job offer seemed unattractive due to the lack of benefits.

unattractive 是由前缀 un-（表示"不、非"）和形容词 attractive（有吸引力的）组成的复合词。attractive 来自动词 attract（吸引）加形容词后缀 -ive。 unattractive 字面意思是"不吸引人的"，引申为"不具吸引力的"。