From The Collaborative International Dictionary of English v.0.48 :
Springiness \Spring"i*ness\ (-[i^]*n[e^]s), n.
The state or quality of being springy. --Boyle.
[1913 Webster]
From WordNet (r) 3.0 (2006) :
springiness
n 1: the elasticity of something that can be stretched and
returns to its original length [syn: give, spring,
springiness]