The phrase "flip side" refers to the opposite or contrasting aspect of a situation or thing. There are many synonyms for this phrase, including the reverse side, the other side, the opposite side, the downside, the negative aspect, the flip-flop, the backside, the underbelly, and the dark side. Each of these synonyms emphasizes a slightly different aspect of the concept of a flip side, from the purely physical (the reverse side) to the more emotional or moral (the underbelly or the dark side). No matter which term you prefer, the flip side is always an important consideration when evaluating any situation or decision.