secret language; code word; argot
Refers to a deliberately concealed or specialized vocabulary used within a group to exclude outsiders or for secrecy.
The spies communicated using a secret language.
In this organization, code words are used so that outsiders cannot understand.
Compound of 暗 (an, 'dark, hidden') and 語 (go, 'word, language'), literally 'hidden words'. The exact historical derivation is uncertain, but the term follows standard Sino-Japanese word formation.