like sin vs like mad

like sin and like mad both are adverbs.

Word	Noun	Adjective	Verb	Adverb
like sin	No	No	No	Yes
like mad	No	No	No	Yes

As adverbs, like sin and like mad are synonyms defined as:

like sin and like mad: (informal) with great speed or effort or intensity; used for emphasis

Other synonyms of like sin include like crazy, like hell, like the devil, like thunder.

like sin (adverb)	like mad (adverb)
(informal) with great speed or effort or intensity; used for emphasis	(informal) with great speed or effort or intensity; used for emphasis