*Jaloux* and *envieux* indeed mean "jealous/envious persons" but are used as substantives here so there is no suppressed noun.

Many descriptive adjectives can be nominalized and have been granted the status of nouns:

> *Tu es entouré de **blondes***.
>
> *Tu arrives dans la cour des **grands***.

same for *ambitieux*, *avare*, *timide*, *méchant*, *gentil*...

Some, like *jaloux* and *envieux*, are not officially nouns but can nevertheless be nominalized, like for example *sales*, *lâches* and *sauvages*.