Como entenderia a sentença acima? O perigo da tradução literal significa nonsense, “qualé, continue com sua camisa!”. A maneira mais apropriada de se traduzir essa frase seria entendendo que “keep one’s shirt on” é uma expressão idiomática que significa “manter a calma.” Vejamos exemplos de seu uso:
Ex.: Keep your cool. Keep your shirt on.
Ex.: Keep your shirt on. It is good for your health.
Ex.: Keep your shirt on. I’ll give you a hand.
Ex.: Keep your shirt on, Harry; we have plenty of time to catch the train.
Ex.: Keep your shirt on, buddy. Talk to him.
Ex.: Keep your shirt on. He didn’t mean to offend you. That’s just the way he talks.
Ex.: The plane doesn’t land for another hour, so keep your shirt on.
Ex.: You just keep your shirt on and listen to me
Ex.: “Honey, keep your shirt on, please! I’m sorry, but the boss made me work late at the office.”
Ex.: Don’t be silly. It’s nothing worth a quarrel, let alone fight. Keep your shirt on.
Fonte: Dicionário de Expressões Idiomáticas de Michaelis.