adjective
lucid
LOO-sid/ˈluːsɪd/
Clear in thought and understanding.
The lucid speaker explains the three steps in a clear sequence.

Etymology
Latin lucidus described brightness and also clarity of meaning. Lucid applies that same connection to thought and expression: what is mentally clear is understood as free from obscurity.
In context
In fact, he was so lucid, so clear, so very strong, you know, very articulate.
More examples
- His lucid explanation makes the complicated rules easy to understand.
- I feel more lucid after a good night's sleep.
- The essay presents a lucid argument for changing the policy.
Forms
lucid · more lucid · most lucid
lucidity noun — Clarity of thought or expression.
lucidly adverb — In a clear, easily understood way.