From BiblePortal Wikipedia

King James Dictionary [1]

H`Ardness, n. See Hard. Firmness close union of the component parts compactness solidity the quality of bodies which resists impression opposed to softness and fluidity.

1. Difficulty to be understood. 2. Difficulty to be executed or accomplished as the hardness of an enterprise. 3. Scarcity penury difficulty of obtaining money as the hardness of the times. 4. Obduracy impenitence confirmed state of wickedness as hardness of heart. 5. Coarseness of features harshness of look as hardness of favor. 6. Severity of cold rigor as the hardness of winter. 7. Cruelty of temper savageness harshness.

The blame

May hang upon your hardness.

8. Stiffness harshness roughness as the hardnesses of sculpture. 9. Closeness niggardliness stinginess. 10. Hardship severe labor, trials or sufferings.

Endure hardness, as a good soldier of Jesus Christ.  2 Timothy 2

Webster's Dictionary [2]

(1): ( n.) The quality or state of being hard, literally or figuratively.

(2): ( n.) The peculiar quality exhibited by water which has mineral salts dissolved in it. Such water forms an insoluble compound with soap, and is hence unfit for washing purposes.

(3): ( n.) The cohesion of the particles on the surface of a body, determined by its capacity to scratch another, or be itself scratched;-measured among minerals on a scale of which diamond and talc form the extremes.