A few more slang terms I have found.
booster: a strong supporter
Example: Sarah was a big booster for the newsies during the strike.
brass: high ranking officials
Example: Pulitzer and Hurst had the brass on their side.
chew the fat: to spend time talking
Example: The older newsies were gathered around just chewing the fat.
ducky: okay; alright
Example: Things were just ducky between Spot and Jack.
eat: to annoy; bother
Example: Davey could tell that something was eating Jack.
hang-out: a gathering place
Example: The docks was the Brooklyn newsies typical hang-out.
jiggy: jittery; fidgety
Example: He was feeling a bit jiggy about selling alone for the first time.
juice: electricity
Example: The lights went out because they were all out of juice.
loaded: drunk; intoxicated
Example: At night, newsies had to be careful for men who came out of the bars loaded.
lush: an alcoholic
Example: It would be bad for a newsie to turn into a lush.
nippy: chilly
Example: The fall weather made things a bit nippy.
nutty: crazy; insane
Example: Davey thought Jack was nutty to think about going on strike.
raggedy: in bad condition
Example: Jack was worried about Crutchy being raggedy.
razzmatazz: something fancy
Example: The theatre was normally razzmatazz, but Medda made it feel homey for the newsies.
schmuck: a jerk
Example: Oscar Delancy was such schmuck, cutting in line like that.
spit and image: an identical copy
Example: Les grew up to be the spit and image of his older brother.
thin ice: a precarious situation
Example: Jack was on thin ice when Pulitzer offered to pay him to stop striking the papers.
skunk: to swindle or cheat
Example: The newsie skunked Davey out of his fifty cents.
two bits: a twenty-five cent piece
Example: Boots wouldn’t give anyone two bits that Spot would miss a shot.
windbag: someone who talks too much
Example: Davey can be such a windbag. He never stops talking.
four-flusher: a person who bluffs and deceives others
Example: To Davey, Jack had been a four-flusher who tried to make him think a strike could work.
grind: a studious, unsociable person
Example: Because Specs liked to study at the library, the other boys felt like he was such a grind.
willies: nervousness from fear
Example: Being chased by the bulls gave Davey the willies.
hotfoot: move quickly
Example: The newsies hotfotted it when they heard the whistle of the police.
plunk down: to pay
Example: Racetrack plunk downed his bets.
digs: home or apartment
Example: Some of the older newsies had enough money to have their own digs outside the lodge.
live wire: and exciting, energetic person
Example: Jack was a live wire who stirred excitement and passion in his fellow newsies
port-sider: a left-hander
Example: The kid was a port-sider.
battle-ax: mean old woman
Example: The battle-ax shooed the newsies with a mean huff.
bumbershoot: an umbrella
Example: The mayor’s daughter sure has a nice bumbershoot.
cheapskate: a stingy person; tightwad
Example: Racetrack thought Pulitzer was a cheapskate.
pinhead: a stupid or foolish person
Example: At first, Spot thought Davey was a pinhead for going on strike.
bonehead: a stupid or foolish person
Example: Don’t be bonehead! It’s a great idea.
do in: to kill or destroy
Example: Crutchy felt that the Delancy brothers did him in.
doll up: dress up; dress stylishly
Example: Davey wondered why Sarah was all dolled up.
double-cross: to betray
Example: The newsies felt that Jack had double-crossed them when they saw him dressed like a scab.
in the bag: assured; guaranteed
Example: Racetrack promised that his tips were in the bag.
jitney: a nickel; a five cent piece
Example: Les spent a jitney on some candy.
just off the boat: naive
Example: Davey acted like he was just off the boat.
lay off: to quit
Example: Lay off, would you? He’s trying to think!
rat: a contemptible person
Example: The newsies viewed Jack as a rat for siding with Pulitzer.
snarky: irritable; short-tempered
Example: Spot could be rather snarky when things didn’t turn out they way he had planned.
tail: to follow
Example: The cops were tailing Jack and Davey through the crowd.
hock: to pawn
Example: Some newsies try to hock their stuff to each other in order to get more money.
beat it: to leave
Example: To quote Racetrack, “he put an egg in his shoe, and beat it.”
gander: a look
Example: Davey took a gander at all the newsies gathered at the theatre.
joint: a questionable establishment
Example. “Medda here owns the joint.”