1. Having unpleasant qualities associated with a degraded or degenerate way of living: The social workers often had to work in the seamiest of housing situations.
2. Unpleasant or sordid, low, disagreeable: The Lime House District in London, in the time of Charles Dickens, was considered one of the seamier districts in the city.
3. A reference to unpleasant and usually illegal things; such as, crime, drugs, prostitution, etc.: Ted was involved in a seamy corruption scandal.
4. Showing where two pieces of fabric have been joined together: The seamstress was careful to eliminate the seamy appearance of the garment she was making.
5. Etymology: from about 1604, in a figurative sense, "seamy side, least pleasant, worst"; from seam, alluding to the underside of a garment on which the rough edges of the seams are visible and less attractive; and therefore, typically turned in.