Having the characteristic of billows; rising and falling in large waves; swelling or surging like ocean waves.
From 'billow' (Old Norse 'bylgja') plus the adjectival suffix '-y,' which converts nouns into descriptive adjectives indicating possession of that quality.
Billowy is the adjective that Romantic poets and historical novelists absolutely love—it's the go-to word for describing silk dresses, sails, and clouds with maximum drama.
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