a person, especially in the western US, whose job is to take care of cattle, and who usually rides a horse, or a similar character in a film

The ranch employed ten or twelve cowboys. 牧场雇了十一二个牛仔。

He was wearing cowboy boots and a cowboy hat. 他脚蹬牛仔靴，头戴牛仔帽。

I don't much like cowboy films/movies. 我不大喜欢看牛仔片。

someone who is not honest, careful, or skilful in their trade or business, or someone who ignores rules that most people obey and is therefore not considered to be responsible

Those builders are a bunch of cowboys - they made a terrible job of our extension. 那些建筑商是一帮不负责任的奸商——他们把我们的扩建工程弄得一团糟。