expression, noun
cowardly backbiting; loser's grumbling
Idiomatic expression likening someone's complaints or insults from a safe distance to a dog barking from afar. Used to dismiss criticism as weak or cowardly.
彼の陰口は犬の遠吠えに過ぎない。
His backbiting is nothing more than a coward's distant barking.
負
Those sour-grapes remarks are just the grumblings of a loser.