Antonyms of adj thunderous

2 senses of thunderous

Sense 1
deafening, earsplitting, thunderous, thundery -- (loud enough to cause (temporary) hearing loss)

INDIRECT (VIA loud) -> soft -- ((of sound) relatively low in volume; "soft voices"; "soft music")

Sense 2
thunderous -- (extremely ominous; "world events of thunderous import")

INDIRECT (VIA unpropitious) -> propitious -- (presenting favorable circumstances; likely to result in or show signs of success; "propitious omens"; "propitious gales speeded us along"; "a propitious alignment of planets for space exploration")

Similarity of adj thunderous

2 senses of thunderous

Sense 1
deafening, earsplitting, thunderous, thundery -- (loud enough to cause (temporary) hearing loss)
       => loud (vs. soft) -- (characterized by or producing sound of great volume or intensity; "a group of loud children"; "loud thunder"; "her voice was too loud"; "loud trombones")

Sense 2
thunderous -- (extremely ominous; "world events of thunderous import")
       => unpropitious (vs. propitious) -- (not propitious)