The phrase "sunk in" can be replaced with a number of synonyms, depending on the context. To express the idea of a realization occurring, one might use the alternatives "dawned on" or "hit home." To describe the idea of accepting a defeat or loss, one could use the synonyms "come to terms with" or "accept." The phrase "sunk in" can also be used in reference to a physical object or person sinking, in which case synonyms like "descend," "droop," and "submerge" might be employed. Overall, there are a range of alternatives available to express the idea conveyed by the phrase "sunk in".