behind someone's back

Idioms and Phrases

Out of one's presence or without someone's knowledge, as in Joan has a nasty way of maligning her friends behind their backs . Sir Thomas Malory used this metaphoric term in Le Morte d'Arthur (c. 1470): “To say of me wrong or shame behind my back.” [Early 1300s]

Related Words

• clandestinely
• covertly
• furtively
• personally
• privately
• quietly
• stealthily
• surreptitiously