IPA: /ˈkrɪp.tə.lɪst/
KK: /ˈkrɪp.tə.lɪst/
A person who studies codes and ciphers to understand and create secure communication.
The cryptologist worked tirelessly to decode the secret messages.
Cryptologist → It is formed from "crypto-" (from Greek "kryptos", meaning hidden or secret) and "-logist" (from Greek "logia", meaning study or science). A cryptologist is someone who studies hidden or secret codes and ciphers.
Think of someone who studies things that are 'hidden' ('crypto-') — that's what a cryptologist does.