in the gutter

Appropriate to or from a squalid, degraded condition. For example, The language in that book belongs in the gutter. An antonym, out of the gutter, means “away from vulgarity or sordidness,” as in That joke was quite innocent; get your mind out of the gutter. This idiom uses gutter in the sense of “a conduit for filthy waste.” [Mid-1800s]