The word amateur has at least two connotations. In the first, more widely used manner, it means someone performing some task without pay, in contrast to a "professional" who would be paid for the same task. In this sense, labeling someone an "amateur" can have a negative connotation. For example, amateur athletes in sports such as basketball or football would not be regarded as having ability on par with professional athletes in those sports.
From
Wikipedia
Of course we know what real amateurs are :)
).