UK and ANZ, US molder [verb] [I] - to decay slowly; to rotI found these apples mouldering in the cupboard.(figurative) That old bike has been mouldering away (= has been left without being used or cared for) in the shed for ages - we should get rid of it.
MOULDER
Meaning of MOULDER in English
Cambridge English vocab. Кембриджский английский словарь. 2012