callow (KAL-oh) - adj., bald, hairless, bare; (of a young bird) unfledged; immature, lacking in life experience.
Which gives the meanings of the word in the order of development -- the extension into unfledged came in the 16th century, and the immature extension of that a little later. In Middle English, it was calwe, bald, from Old English calu, same meaning, from Proto-Germanic *kalwaz, bald/bare, from PIE gel(H)wo-, bare/bald. (A very large percentage of IE languages have their word for bald from this root -- the English word is uncertain, but is speculated to have come about in Middle English by comparisons with a ball.)
---L.
Which gives the meanings of the word in the order of development -- the extension into unfledged came in the 16th century, and the immature extension of that a little later. In Middle English, it was calwe, bald, from Old English calu, same meaning, from Proto-Germanic *kalwaz, bald/bare, from PIE gel(H)wo-, bare/bald. (A very large percentage of IE languages have their word for bald from this root -- the English word is uncertain, but is speculated to have come about in Middle English by comparisons with a ball.)
---L.