mettere in guardia

Literally, “to put in guard/watch”, or more loosely translated as “to put on guard”.

méttere in guardia (first-person singular present métto in guardia, first-person singular past historic mìsi in guardia, past participle mésso in guardia, auxiliary avére)

1. (transitive, intransitive, idiomatic) to warn; to caution

   Synonyms: avvisare, ammonire

   • 2020, Barack Obama, chapter 12, in Chicca Galli, Paolo Lucca, Giuseppe Maugeri, transl., Una terra promessa [A Promised Land], Garzanti Libri:

     Tim, dall'altra parte, metteva in guardia sul fatto che simili atteggiamenti populisti potessero rivelarsi controproducenti, spaventando tutti quegli investitori di cui avevamo bisogno per ricapitalizzare le banche.

     Tim, on the other hand, warned that such populist gestures would be counterproductive, scaring off the investors we needed to recapitalize the banks.

     (literally, “Tim, on the other hand, warned about the fact that similar populist attitudes could prove themselves counterproductive, scaring all those investors whom we needed to recapitalize the banks.”)