IPA: //ˈklaʊdˌbɜːrst//
KK: /ˈklaʊdˌbɜrst/
A sudden and very heavy rain that falls in a short period of time.
The cloudburst caused flash flooding in the streets.
Cloudburst is formed from "cloud" (from Old English "clud", meaning a mass of vapor or moisture in the sky) and "burst" (from Old English "berstan", meaning to break open or explode). The word describes a sudden and intense rainfall that seems to burst from the clouds.
Imagine a mass of vapor ('cloud') suddenly 'breaking open' ('burst') to release a heavy downpour — that's what a cloudburst means.
No commonly confused words.