Secret; hidden; concealed. The “clandestine importation” of goods is a term used in English statutes as equivalent to “smuggling.” Keck v. U. S., 172 U. S. 434, 19 Sup. Ct 254, 48 I Ed. 505. A clandestine marriage is (legally) one contracted without observing the conditions precedent prescribed by law, such as publication of bans, procuring a license, or the like.