The Collaborative International Dictionary of English v.0.48:

Clancular \Clan"cu*lar\, a. [L. clancularius, from clanculum
   secretly, adv. dim. of clam secretly.]
   Conducted with secrecy; clandestine; concealed. [Obs.]
   [1913 Webster]

         Not close and clancular, but frank and open. --Barrow.
   [1913 Webster]