philanderer vs masher

philanderer and masher both are nouns.

Word	Noun	Adjective	Verb	Adverb
philanderer	Yes	No	No	No
masher	Yes	No	No	No

As nouns, masher is a hyponym of philanderer; that is, masher is a word with a more specific, narrower meaning than philanderer:

philanderer: a man who likes many women and has short sexual relationships with them
masher: a man who is aggressive in making amorous advances to women

Other hyponyms of philanderer include Casanova, Don Juan, Lothario, skirt chaser, wolf, woman chaser.

philanderer (noun)	masher (noun)
a man who likes many women and has short sexual relationships with them	a kitchen utensil used for mashing (e.g. potatoes)
	a man who is aggressive in making amorous advances to women