thunderhead (noun) cloud: mass of water particles in air
Sinonime: billow, brume,
darkness, dimness,
film,
fog, fogginess,
frost,
gloom,
haze, haziness, mare's tail,
mist, murk, nebula, nebulosity,
obscurity, ol' buttermilk sky, overcast, pea soup, pother, puff, rack, scud, sheep, smog,
smoke,
smother, steam, thunderhead, vapor,
veil, woolpack