Callow, a.
Etymology: [OE. calewe, calu, bald, AS. calu; akin to D. kaal, OHG. chalo, G. Kuhl; cf. L. calvus.]
1. Destitute of feathers; naked; unfledged. An in the leafy summit, spied a nest, Which, o'er the callow young, a sparrow pressed. Dryden.
2. Immature; boyish; "green"; as, a callow youth. I perceive by this, thou art but a callow maid. Old Play [1675].
1 other Webster entry under this spelling
Callow, n. (Zoöl.)
A kind of duck. See Old squaw.
Shades of meaning
Fernald has no entry of its own for callow; he lists it under youthful.
He lists it without comment; the entries above explain its neighbors.