The sales representative was investigated for offering kick-backs to doctors to promote the drugs.

kick-backs 是由动词短语 kick back 加连字符构成的复合名词。kick back 原意是"踢回"，引申为"返还"。 kick-backs 在商业语境中特指"回扣"，即为了获得不正当商业利益而支付的秘密款项。这种回扣通常是暗中进行的非法行为。