The Collaborative International Dictionary of English v.0.48:

Viscidity \Vis*cid"i*ty\, n. [Cf. F. viscidit['e].]
   The quality or state of being viscid; also, that which is
   viscid; glutinous concretion; stickiness.
   [1913 Webster]

WordNet (r) 3.0 (2006):

viscidity
    n 1: the property of being cohesive and sticky [syn:
         cohesiveness, glueyness, gluiness, gumminess,
         tackiness, ropiness, viscidity, viscidness]