Noah Webster
Perspicuity
PERSPICU'ITY, noun [Latin perspicuitas, from perspicio.]
1. Transparency; clearness; that quality of a substance which renders objects visible through it. [Little Used.]
2. Clearness to mental vision; easiness to be understood; freedom from obscurity or ambiguity; that quality of writing or language which readily presents to the mind of another the precise ideas of the author. perspicuity is the first excellence of writing or speaking.