asperity (n.)

c. 1200, asprete "hardship," from Old French asperité "difficulty, painful situation, harsh treatment" (12c., Modern French âpreté), a figurative use, from Latin asperitatem (nominative asperitas) "roughness," from asper "rough, harsh," which is of unknown origin. The Latin adjective was used also of sour wine, bad weather, and hard times. Figurative meaning "harshness of feeling" in English is attested from 1660s; literal sense of "roughness of surface" is from early 15c.