cryptonym

[ krip-tuh-nim ]
/ ˈkrɪp tə nɪm /

noun

a secret name or word; a code name or code word.
Related formscryp·ton·y·mous [krip-ton-uh-muh s] /krɪpˈtɒn ə məs/, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019