The Collaborative International Dictionary of English v.0.48:

Cling \Cling\ (kl[i^]ng), v. i. [imp. & p. p. Clung
   (kl[u^]ng), Clong (kl[o^]ng), Obs.); p. pr. & vb. n.
   Clinging.] [AS. clingan to adhere, to wither; akin to Dan.
   klynge to cluster, crowd. Cf. Clump.]
   To adhere closely; to stick; to hold fast, especially by
   twining round or embracing; as, the tendril of a vine clings
   to its support; -- usually followed by to or together.
   [1913 Webster]

         And what hath life for thee
         That thou shouldst cling to it thus?     --Mrs. Hemans.
   [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

20 Moby Thesaurus words for "clinging":
   adhering, adhesion, agglutinate, bond, cleaving, cling, coherence,
   coherent, cohering, cohesion, cohesive, grasping, gripping,
   holding, holding together, keeping, retentive, sticking, stuck,
   tenacious