Opportunistically is an adverb used to describe a situation where someone takes advantage of an opportunity without regard for the consequences. There are several other words that can be used interchangeably with opportunistically, including self-serving, exploitative, and mercenary. Self-serving refers to acting in one's own interest to the detriment of others. Exploitative describes someone who takes advantage of others for personal gain. Mercenary implies that someone is motivated solely by money or reward. Each of these synonyms emphasizes a different aspect of the opportunistic behavior. Regardless of the word used, the behavior is generally seen as negative and lacking in ethical considerations.