callow

from The American Heritage® Dictionary of the English Language, 5th Edition.

• adjective Lacking adult maturity or experience; immature.

from The Century Dictionary.

• noun In entomology, an insect just emerged from its cocoon: especially applied to ants.
• Bald; without hair.
• Without feathers; that has not yet put forth feathers; naked; unfledged, as a young bird: as, “callow young,”
• Pertaining to an unfledged bird: as, “callow down,” Drayton, The Owl.
• Youthful; juvenile; very immature: as, a callow youth.
• noun A bald person; a baldhead.
• noun An alluvial flat along a river-course: a term used by writers on Irish geology and agriculture.
• noun In coal-mining, the baring, or cover, of open workings.
• Having the character of an alluvial flat: as, callow land; a callow meadow.

from the GNU version of the Collaborative International Dictionary of English.

• adjective Destitute of feathers; naked; unfledged.
• adjective Immature; boyish; “green”.
• noun (Zoöl.) A kind of duck. See old squaw.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective obsolete Bald.
• adjective Unfledged (of a young bird).
• adjective Immature, lacking in life experience.
• adjective Lacking color or firmness (of some kinds of insects or other arthropods, such as spiders, just after ecdysis). Teneral.
• adjective Shallow or weak-willed.
• adjective Unburnt (of a brick)
• noun A callow young bird.
• noun A callow or teneral phase of an insect or other arthropod, typically shortly after ecdysis, while the skin still is hardening, the colours have not yet become stable, and as a rule, before the animal is able to move effectively.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• adjective young and inexperienced