The term "dark lamp" can be described through various synonyms. The word "gloomy lamp" would perfectly convey the idea of a light source that does not give off enough brightness to illuminate the surrounding area. Another applicable synonym could be "dim lamp," which indicates that the light it emanates is not vibrant or intense. "Dusky lamp" could be used to depict a lamp with a slight tint or faint light. Another possible option is "shadowy lamp," which suggests that the lamp emits a weak light that is only enough to create an obscure ambiance. In essence, these synonyms provide various ways to describe a lamp that does not give off enough light.