The word "bottom-feeding" is often used in a negative sense to describe someone who is a parasite and preys on vulnerable individuals or communities. Some synonyms for this term include leeching, mooching, scavenging, and exploiting. These words all imply a similar behavior of taking advantage of others for personal gain. Other related words include opportunistic, parasitic, or predatory, which further emphasize the negative connotations associated with someone who engages in such behavior. It's important to recognize and avoid individuals or groups who engage in bottom-feeding behaviors, as their actions have the potential to harm others and create a negative impact on society as a whole.