There are a variety of synonyms for the word "rubberinesses" that can be used to convey the idea of something being elastic or pliable. These could include terms like stretchiness, flexibility, resilience, suppleness, or springiness. Other related words might include terms like bounce, buoyancy, or tension, which all refer to different aspects of elasticity or physical properties of materials. Ultimately, the choice of synonym will depend on the specific context in which the term is being used and the desired connotations or associations that the speaker or writer is trying to convey.