a strategy, attempt, or device to to conceal or hide (cover) something, especially to prevent people from finding out about a mistake, crime, or unethical/illegal situation;
e.g. He told an elaborate story as a cover-up for his error in judgement.
(noun)
an outer garment, usually loose-fitting, that is worn over another outfit such as exercise clothes or a swimsuit;
e.g. She took off her cover-up on the pool deck and then jumped into the water.