solidness

(noun) the state in which a substance has no tendency to flow under moderate stress; resists forces (such as compression) that tend to deform it; and retains a definite size and shape. Synonyms: solid, solid state.

(noun) the consistency of a solid. Synonyms: solidity.

(noun) the quality of being substantial or having substance. Synonyms: substantiality, substantialness.

(noun) the quality of being solid and reliable financially or factually or morally. Synonyms: solidity. Examples: "The solidity of the evidence worked in his favor." "The solidness of her faith gave her enduring hope."