We have put together a list of words that are similar to THUNDEROUS.

6 Alternative Words Similar to thunderous

1 Deafening Adjective      Synonym Words Like Deafening
2 Earsplitting Adjective      Synonym Words Like Earsplitting
3 Thundery Adjective      Synonym Words Like Thundery
4 Roaring Adjective      Synonym Words Like Roaring
5 Loud Adjective      Similar Words Like Loud
6 Unpropitious Adjective      Similar Words Like Unpropitious

9 definitions of thunderous

1 Producing thunder.
2 Making a noise like thunder; sounding loud and deep; sonorous.
3 loud enough to cause (temporary) hearing loss
4 extremely ominous
5 Producing thunder or a similar sound.
6 Loud and unrestrained in a way that suggests thunder: thunderous applause.
7 Thunder-producing; betokening thunder; awful.
8 Thundering; loud and deep-sounding; making a noise like thunder.
9 Very loud; suggestive of thunder
We get our data from many different dictionaries across the web:
Wordnik, Wiktionary, Century, American Heritage, Gcide