In general, a lodge or a Mason is clandestine when not legally constituted or made. But “not legally constituted” may not necessarily mean “clandestine.” A Fellowcraft receiving the Master Mason degree in a lodge in which the Charter has been lost is not “legally” made and must be reobligated to be “healed,” but such a making is not “clandestine.” The clandestine lodge today is one which is set up by an unrecognized Grand Lodge which is spurious, unlawful. Any group of men-even men not Masons might declare themselves a lodge and “make Masons,” but all these actions, being illegal, would produce only a clandestine lodge and clandestine Masons.
Modern scholarship distinguishes between the “clandestine” and the “not recognized.” For instance not necessary to go into here, the Grand Lodges of Ireland and of Utah are not in fraternal relations each with the other. But no Utah Mason would term the Irish Grand Lodge “clandestine”; he would say merely that it is “unrecognized.”