WordWeb Online

1. Clear and bright
   "limpid blue eyes"
   - liquid
    
2. Transmitting light; able to be seen through with clarity
   "could see the sand on the bottom of the limpid pool"
   - crystalline, crystal clear, lucid, pellucid, transparent
    
3. (of language) transparently clear; easily understandable
   "writes in a limpid style"
   - lucid, luculent, pellucid, crystal clear, perspicuous

See also: clear, limpidity