Thumbs down is a lowered thumb meaning bad or refused. Give it the thumbs down, thumbs down from the panel, a firm thumbs down.
The Roman gladiatorial gesture everybody cites is not securely understood, and the modern meanings of the thumb may be the reverse of the ancient ones. What is certain is that the gesture is offensive in several countries.
1phrasethumbs downA lowered thumb meaning bad or refused.
“The kids took one spoonful of the broccoli soup and gave it a thumbs down.”
thumbs down is a gesture.
From the gesture, popularly traced to Roman gladiatorial contests though the ancient meaning is uncertain.
See thumbs up.
Etymology from Wiktionary, CC BY-SA
Practised in Body Language & Gestures