noun. the quality of smelling or tasting old or stale or mouldy.
1. Noun, singular or mass The best way to use vinegar is to mix it right for the level of mustiness in the cabinet, and to give it time to eradicate the smelly issue. 2. Verb, base form A combination of warm temperatures, high humidity and stagnant air is an invitation to mustiness in organic fabrics such as linen, cotton or other natural and some synthetic fibers and fillings.