supergrass vs informer

supergrass and informer both are nouns.

Word	Noun	Adjective	Verb	Adverb
supergrass	Yes	No	No	No
informer	Yes	No	No	No

As nouns, informer is a hypernym of supergrass; that is, informer is a word with a broader meaning than supergrass:

supergrass: a police informer who implicates many people
informer: one who reveals confidential information to the police or other authority

Other hypernyms of supergrass include betrayer, blabber, rat, squealer.

supergrass (noun)	informer (noun)
a police informer who implicates many people	one who reveals confidential information to the police or other authority