The word "slimeball" has negative connotations and is often used to describe someone who is deceitful, dishonest, or disreputable. However, there are several other synonyms that can be used to describe such a person. One of them is "weasel," which implies that the person is sneaky and untrustworthy. Another synonym is "snake," which suggests that the person is cunning and manipulative. "Sleazebag" is also a common synonym that refers to someone who is morally corrupt or lacking in integrity. Lastly, "scumbag" is a term used to describe a contemptible or despicable person. All of these words can serve as alternatives to "slimeball" depending on the tone and context of the conversation.