thundercloud

A large dark cloud charged with electricity and producing thunder and lightning; a cumulonimbus cloud.

Something menacing or dreadful.

A cloud that produces lightning and thunder.

A cloud charged with electricity, and producing lightning and thunder.

a large, dark cloud, usually a cumulonimbus, charged with electricity and producing thunder and lightning; a stormcloud

something menacing and brooding

a dark cloud of great vertical extent charged with electricity; associated with thunderstorms