like mad vs like thunder

like mad and like thunder both are adverbs.

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

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

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

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

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