ADJ

dense, heavy, thick
light
fluffy
cirrus, cumulus
high, low
broken, scattered
skies of broken cloud
fast-moving, scudding
black, dark, grey, white
rain, storm, threatening, thunder
Rain clouds were looming on the horizon

QUANT

band, bank, layer, mass, wisp
a layer of high cloud

VERB + CLOUD

seed (= to place a substance in a cloud to make it produce rain)

CLOUD + VERB

form, gather, mass
Dark clouds were gathering in the west
cover sth, envelop sth, obscure sth
break, clear, disperse, lift, part
The clouds broke a little, and the sun came out
drift, float, hang, hover, loom, move, pass, race, roll, scud, swirl
Thick cloud hung over the moor. A cloud passed over the sun. White clouds scudded across the sky

CLOUD + NOUN

bank, cover, formation
The cloud cover is quite dense today

PREP

above/below the ~s
flying above the clouds
through the ~s
She could see the sun through the clouds

PHRASES

a break in the cloud(s), a layer of cloud

ADJ

great, huge
a great cloud of grey smoke
dense, thick
billowing, swirling
mushroom
the mushroom cloud from a nuclear bomb
dust, radioactive, smoke

PREP

~ of
a thick cloud of steam