A greaser, in this meaning, is a young man — especially in the US around the 1950s — who cares a lot about motorcycles and cars, wears his hair shiny with grease, and acts tough. Think of a leather jacket, jeans, a comb in the pocket, hanging around a garage.

A greaser, in this meaning在這個意思裡, greaser is是 a young man一個年輕男生 — especially尤其是 in the US around the 1950s1950年代左右的美國 — who cares a lot about motorcycles and cars很在乎摩托車和汽車, wears his hair shiny with grease把頭髮抹得油亮, and acts tough而且裝得很屌。Think of想像 a leather jacket一件皮外套, jeans牛仔褲, a comb in the pocket口袋裡插一把梳子, hanging around a garage在修車廠附近晃來晃去。

The name comes from grease: mechanics get greasy at work, and these young men greased their hair. Films and books made the look famous, so people still use the word for that style.

The name這個名字 comes from來自 greasegrease（油）: mechanics技工 get greasy at work上班會弄得滿手油, and而 these young men這些年輕人 greased their hair把頭髮抹了油。Films and books電影和書 made the look famous讓這個造型出名, so所以 people still use人們現在還用 the word這個字 for that style來講那種風格。

It is informal. It can sound rough, or a bit admiring, depending who says it.

It is這是 informal口語詞。It can sound聽起來可能 rough很粗魯, or也可能 a bit admiring帶點欣賞, depending who says it要看是誰在說。

Though actually the same word has also been used as a rude name for Mexican people and for Italian-Americans, from old, unkind ideas about greasy hair. That use is offensive. The meaning here is the car-and-motorcycle young man.

Though actually不過其實 the same word同一個字 has also been used也被用來 as a rude name當作粗魯稱呼 for Mexican people and for Italian-Americans對墨西哥人和義大利裔美國人的, from old, unkind ideas about greasy hair源自以前對油頭的不友善印象。That use那種用法 is是 offensive冒犯的。The meaning here這裡講的意思 is是 the car-and-motorcycle young man那種愛車愛機車的年輕人。