very clear and easy to understand; able to think clearly
Words It Might Replace:
clear, logical, orderly (describing an explanation); rational (describing a person). The word's original meaning, by the way, is "suffused with light."
"But instead of a lucid narrative explaining what happened when the economy imploded in 2008, why, and who was to blame, the report is a confusing and contradictory mess..." Frank Partnoy, The New York Times, January 29, 2011