Spitting Image, a colloquial phrase often used to describe someone who is strikingly similar to another, has several antonyms that imply disagreement or dissimilarity. "Polar opposite," for instance, connotes the idea of something being diametrically opposed to another, while "unlike" suggests dissimilarity or contrast. "Incompatible," on the other hand, denotes an incapability to exist or work together, while "discordant" implies a lack of harmony or agreement. "Dissimilar," "contrasting," and "unequal" are other antonyms for spitting image that highlight the differences between two individuals or things. In essence, these words paint a picture of two things that are vastly disparate, contrasting, or incompatible.