callow

[Origin: Old English 'calu' - bare, bald, probably from West Germanic '*kalwaz', perhaps from Latin or Celtic. From young birds with no feathers, meaning extended to any young inexperienced thing or creature (1580)]

adj.
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].

n.
3. A recently hatched worker ant.