1. 
[syn: limpid, lucid, luculent, pellucid, crystal clear, perspicuous]
The Collaborative International Dictionary of English v.0.48:
Luculent \Lu"cu*lent\, a. [L. luculentus, from lux, lucis,
   light.]
   1. Lucid; clear; transparent. --Thomson.
      [1913 Webster]
   2. Clear; evident; luminous. " Most luculent testimonies."
      --Hooker.
      [1913 Webster]
   3. Bright; shining in beauty. [Obs.]
      [1913 Webster]
            Most debonair and luculent lady.      --B. Jonson.
      [1913 Webster]
WordNet (r) 3.0 (2006):
luculent
    adj 1: (of language) transparently clear; easily understandable;
           "writes in a limpid style"; "lucid directions"; "a
           luculent oration"- Robert Burton; "pellucid prose"; "a
           crystal clear explanation"; "a perspicuous argument"
           [syn: limpid, lucid, luculent, pellucid, crystal
           clear, perspicuous]