precious: [13] Latin pretiōsus ‘expensive, valuable, precious’ was derived from pretium ‘price’ (source of English praise, price, and prize). English acquired it via Old French precios. The sense ‘affected’ was introduced from French in the early 18th century. => praise, price, prize
precious (adj.)
mid-13c., from Old French precios "precious, costly, honorable, of great worth" (11c., Modern French précieux), from Latin pretiosus "costly, valuable," from pretium "value, worth, price" (see price (n.)). Meaning "over-refined" in English first recorded late 14c. In Johnson's day, it also had a secondary inverted sense of "worthless." Related: Preciously; preciousness.
precious (n.)
"beloved or dear person or object," 1706, from precious (adj.).