yǐn​yǔ

cryptic language

隐语 隱語 yǐn​yǔ
cryptic language
Language used to suggest something indirectly, such as a riddle, parable, or enigmatic wording; a precursor to the modern 谜语 mí​yǔ
secret code
Secret language shared only within a specific group, such as jargon, argot, or a codeword.

Frequency

Movie subtitles
0.060 per million appears in 0% of films
Written text
0.209 per million

Sources