Under the shelter of darkness is a phrase that usually refers to performing an action secretly or under the cover of night. It is commonly used in literature, music, and movies to describe something hidden or secretive. There are several synonyms for this phrase that one can use to add variety to their writing. Some of the synonyms for under the shelter of darkness include covertly, clandestinely, furtively, stealthily, surreptitiously, privately, and in secrecy. All these words evoke the same sense of secrecy and are perfect substitutes for the phrase under the shelter of darkness. Using these synonyms can help to make your writing more vivid and engaging.