An armchair quarterback
An armchair quarterback (Inglese) — Someone who doesn't engage in a task, job, activity directly and critiques without direct involvement or initiative. This eliminates any failure or injury.
Literally it is a person who sits in a cushioned chair (usually on front of a television) and critiques the players and coaches of an American football game.
An armchair quarterback — телезритель, критикующий действия игроков или тренера; советчик-дилетант