Tenebrously is an adverb that means darkly, obscurely, or mysteriously. It suggests a sense of gloom or obscurity, and can be used to describe anything from a dimly-lit room to a complex situation with unclear outcomes. Synonyms for tenebrously include dimly, somberly, shadowily, murkily, cloudily, enigmatically, and cryptically. These words can all be used to convey a similar sense of darkness or ambiguity, but each has its own connotations and nuances. For example, "enigmatically" suggests a puzzle to be solved, while "cryptically" implies a hidden meaning or message. The choice of synonym will depend on the context and intended meaning of the sentence.