Pert. to; hidden; secret.
- Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874. (adjective) (adj.) (adjective)
Hidden; secret; occult.
- Newage Dictionary DB (adjective) (adj.) (adjective)
Hidden; secret; as, cryptic signs on tombs.
- The Winston Simplified Dictionary. By William Dodge Lewis, Edgar Arthur Singer. Published 1919. (adjective) (adj.) (adjective)

Usage examples:

" You could do it in half that time if you lived in Tinkletown," was Anderson's cryptic return.
- Anderson Crow, Detective by George Barr McCutcheon
I don't like cats as is women, was Alec's cryptic reply.
- Anne Of The Island by Lucy Maud Montgomery
This obligation was either superfluous, every state being obliged to respect the independence of every other, or else it had a cryptic meaning which would only reveal itself in the application of the clause.
- The Inside Story Of The Peace Conference by Emile Joseph Dillon