"Seamiest", referring to something sordid, disreputable, or morally corrupt, could be substituted with various synonyms that evoke similar connotations. An alternative term would be "grittiest", describing a situation or environment that is rough, raw, or unpleasant. Similarly, "sleaziest" can be used to indicate something characterized by dishonesty, trickery, or immorality. "Vilest" is another synonym, highlighting extreme wickedness or repulsiveness. Furthermore, one could employ the word "scuzziest", conveying a sense of being dirty, degraded, or unsavory. All these terms capture the essence of "seamiest" and serve as suitable replacements depending on the context and desired tone of the communication.