IPA: /ˈkrɪp.tə.nɪm/
KK: /ˈkrɪptəˌnɪm/
A word or name that is used in secret to refer to something else, often as a code name.
The spy used a cryptonym to protect his true identity during the mission.
Cryptonym → It is formed from "crypto-" (from Greek "kryptos", meaning hidden or secret) and "-nym" (from Greek "onuma", meaning name). The word "cryptonym" refers to a name that is hidden or secret, often used to conceal the identity of a person or thing.
Think of 'hidden' ('crypto-') names ('-nym') — that's what a cryptonym is, a name that keeps someone's identity secret.
No commonly confused words.