You can picture someone pushing forward through a crowd and never stopping: quick on their feet, quick with their mouth, always moving toward the next chance. Where that push goes is what changes from sense to sense. Point it at work and people admire it. Point it at your wallet and it is a crime.
From the verb hustle plus -er: the one who hustles. The source records the plainest reading of the noun as one who rushes or hurries, which is the picture the other senses grow out of.
hustler 是 hustle 加上 -er，字面就是「做 hustle 的人」。來源裡最素樸的一條解釋是「一個急著趕、動個不停的人」，其他幾個意思都可以想成從這個畫面長出來的。
Wiktionary entry for hustler (local kaikki extract, source_ref kaikki:3f6f69a190036ae4:1168701561): From hustle + -er; sense 0 glossed as one who rushes or hurries; an energetic person.
Three branches
那股停不下來的勁
這一格離核心畫面最近：只有那股推的力氣，還沒有決定要推去哪裡。
noun · B2
Someone who works with restless energy and never stops pushing: chasing chances, selling, starting things. In business talk it is usually praise, but it is also used for a person who is expected to give up everything for the work.
很拚的人
把那股勁用在騙人身上
同一股勁，方向轉到你的口袋。快嘴和演技本身沒變，變的是他用它來換錢。
noun · B2
Someone who tries to trick people out of their money, usually by seeming friendly, harmless, or not very skilled until the money has changed hands. Used especially in American English.
騙錢的人
在街頭靠身體討生活
這一格跟核心的連結，是同一個街頭世界和同一種「靠自己張羅到明天」的生存方式，屬於用法上的靠近，不是歷史上另一條來源。放在這裡是為了讀者在同一本小說裡遇到兩種意思時分得出來。
noun · C1
In American English, a person who sells sex for money — according to the source evidence, most often a man who sells sex to men.
賣春者（多指男性）