Meaning

noun a man who is aggressive in making amorous advances to women

noun a kitchen utensil used for mashing (e.g. potatoes)

originEither by analogy with masher (“one who presses, softens”), or more likely from Romani masha (“a fascinator, an enticer”), mashdva (“fascination, enticement”). Originally used in theater, and recorded in US in 1870s. Either originally borrowed as masher, from masha, or from mash + -er.

Etymology from Wiktionary, CC BY-SA 3.0