Example : Writes in a limpid style.
Lucid directions.
A luculent oration.
Pellucid prose.
A crystal clear explanation.
A perspicuous argument.

Synonyms : crystal clear, limpid, luculent, pellucid, perspicuous

Example : A lucid moment in his madness.

Example : A lucid thinker.
She was more coherent than she had been just after the accident.

Synonyms : coherent, logical

Example : The cold crystalline water of melted snow.
Crystal clear skies.
Could see the sand on the bottom of the limpid pool.
Lucid air.
A pellucid brook.
Transparent crystal.

Synonyms : crystal clear, crystalline, limpid, pellucid, transparent