Definition of cautious. : careful about avoiding danger or risk cautious investors cautious optimism.
37 CFR 5.2 Secrecy order. ( 1 a) When notified by the chief officer of a defense agency that publication or disclosure of the invention by the granting of a patent would be detrimental to the national security, an order that the invention be kept secret will be issued by the Commissioner for Patents.
A secret may be innocent; it is merely something done without the knowledge of others, and nothing is more common; but a clandestine act is one done in such a way as to elude observation. Clandestine Masonry is a bad kind of irregular and unlawful secret society falsely claiming to be Masonic.