Answer:

younger

Answer	Crossword Clue
YOUNGER	One of "Quantrill's raiders"
YOUNGER	Junior
YOUNGER	Less mature

YOUNGER	Not as advanced
YOUNGER	More juvenile.
YOUNGER	The way everyone wants to look.
YOUNGER	Less experienced.
YOUNGER	Less mature.
YOUNGER	More callow
YOUNGER	"... Than Springtime"
YOUNGER	Confederate of Jesse James

YOUNGER	Less aged
YOUNGER	Son's designation, with "the"
YOUNGER	Not so far along
YOUNGER	Like a person's junior
YOUNGER	Less hoary
YOUNGER	Outlaw Cole
YOUNGER	How hair dye may make you look
YOUNGER	Like Princess Leia vis-a-vis Luke Skywalker