adjective/de ˌtɾes ˌpaɾes de naˈɾiθes/
whopping great; a helluva (used to make emphatic)
“uno se pone triste y de mal humor y le entra una melancolía de tres pares de narices” — one gets sad and in a bad mood and a mighty big melancholy comes over them
Synonyms: de narices
Literally, “of three pairs of noses”.