Intelligible
Etymology: [L. intellegibilis: cf. F. intelligible. See Intelligent.]
Capable of being understood or comprehended; as, an intelligible account or description; intelligible pronunciation, writing, etc. The intelligible forms of ancient poets. Coleridge.
Syn. -- Comprehensible; perspicuous; plain; clear.
Shades of meaning
Fernald has no entry of its own for intelligible; he lists it under clear.
He lists it without comment; the entries above explain its neighbors.