During which no phase of the Moon is visible to provide light(adjective)
Having no orbitting moon(adjective)
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Use "moonless" in a sentence
"The young crescent moon had risen, a circumstance which Medea declared enabled her to see more clearly into the future than she could do at the time of the Luna-negers as she called the moonless night."
"Now I can tell you about the time I got my limit of snipes ... it was a dark and moonless night in a midwestern cow pasture ...."
"With officials at the CIA and the White House watching on television monitors, tensions increased when one of the two Black Hawk helicopters lowered into the compound and, beneath a moonless sky, fell heavily to the ground."