The Collaborative International Dictionary of English v.0.48:

Tensility \Ten*sil"i*ty\, n.
   The quality or state of being tensile, or capable of
   extension; tensibility; as, the tensility of the muscles.
   --Dr. H. Mere.
   [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

37 Moby Thesaurus words for "tensility":
   adaptability, agreeability, amenability, bendability, ductibility,
   ductility, elasticity, extendibility, extensibility, facility,
   fictility, flexibility, flexility, flexuousness, formativeness,
   give, impressionability, limberness, litheness, malleability,
   moldability, plasticity, pliability, pliancy, receptiveness,
   responsiveness, sensibility, sensitiveness, sequacity, springiness,
   submissiveness, suppleness, susceptibility, tensileness,
   tractability, tractility, willowiness