1. [informal] (of a cost) unreasonably high or excessive
   "The restaurant charged eye-watering prices for basic dishes";";
   - exorbitant, extortionate, outrageous, steep, unconscionable, usurious [formal], exhorbitant [non-standard]
    
2. Causing the eyes to water or tear up
   "The eye-watering smell of onions filled the kitchen"

See also: immoderate