Usage 1: Today's word is used mostly in reference to young birds and people. However, callow foxes might learn a valuable lesson practicing their attack tactics on a porcupine or skunk. The adverb for this word is "callowly" and the noun, "callowness."
Suggested usage: Edith Wharton pretty much summed up her reasons for relocating to Paris in a letter to a friend after her car broke down in Massachusetts and she was forced to overnight in a hotel less fashionable than she was accustomed to: "Such dreariness, such whining callow women, such utter absence of the amenities, such crass food, crass manners, crass landscape!" So, what happened to the Age of Innocence? Callowness, however, can also be associated with things other than birds and people: "I fear this vintage is wasted on such a callow palate as Freddy's."
Etymology: From Middle English calwe "bald" from Old English calu "bald," related to German kahl "bald" and Latin calvus "bald." On the surface, today's word seems self-contradictory. Baldness usually comes with age and experience yet this word has come to roost on young people with hair at its thickest. How come? As the word "bald" pushed "callow" aside, "callow" reoriented itself to the featherless state of unfledged baby birds—a meaning that it retains, by the way. From here the implication of immaturity migrated back to people, leaving an interesting semantic trail if you have a map. (A gracious bow to Lynn Laboriel, who loves lexical mysteries like that hidden in today's word.)