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.