hello
i want to know if these words are compound or not :

ultrasound - radiography - understand - smallpox - interview - cupboard .

what are the ways by which I can tell if this word is compound OR NOT ?

thanks .

A compound noun is one comprising at least two words. (Sometimes, they are hyphenated.) For example:

Manhunt
Eyewitness
Forget-me-not (a type of flower)

The individual words should stand out as separate words. You shouldn't have to force them. UNDER and STAND are individual words, but UNDERSTAND is not a compound noun. And, that's the hard part. (Usually the individual words are nouns.)