If "sublime" refers to something awe-inspiring and majestic:
* Mundane: Commonplace, ordinary, boring
* Trivial: Unimportant, insignificant
* Banal: Lacking originality, commonplace
If "sublime" refers to something excellent and perfect:
* Mediocre: Average, unremarkable
* Inferior: Of lower quality
* Defective: Flawed, imperfect
If "sublime" refers to something lofty and elevated:
* Base: Low, vulgar, unworthy
* Common: Ordinary, unrefined
* Degrading: Morally low, shameful
Ultimately, the best antonym for "sublime" will depend on the specific context and the nuance you're trying to convey.