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Etymology
, literally “behind one’s back”

Phrase

 * 1)  behind someone's back when someone is not present
 * 2)  behind someone's back without somebody's knowledge, deliberately leaving someone out
 * 1)  behind someone's back without somebody's knowledge, deliberately leaving someone out

Declension

 * The noun takes the appropriate possessive suffix according to the subject of the sentence:, , , , ,.
 * The postposition remains unchanged.