Entry 1 sense Webster, 1913 Cleanser /(klĕnz"ẽr)/ · Cleans·er · IPA /klˈɛnzər/ 01 n. One who, or that which, cleanses; especially, a detergent or other preparation used for cleaning. 1. One who, or that which, cleanses; especially, a detergent or other preparation used for cleaning. Syn. cleansing agent, cleaner.