To Give the Thumbs Up is a sign of approval, often given as a gesture, while Thumbs Down indicates disapproval. Both gestures are used throughout the world, regardless of language or culture, and their origin can be found in the Roman amphitheatres of two thousand years ago.
Se un gladiatore si trovava in balia del suo avversario, avrebbe chiesto all’imperatore un gesto di pollice in su per mostrare approvazione per le sue abilità di combattimento. Se la folla gridasse
meaning ‘let him go free’, then a thumbs-up gesture would follow and he would be spared.
At the very last he would hope to see a closed-hand gesture (pollicem comprimere) as an indication that he had fought well.
But the thumbs in a downward position and the chant of
meant a horrible end for the poor chap in front of thousands of Romans baying for his blood.