A politician to me is always a person whose job is politics. And in fact, being from a democracy, a politician is always someone who has been elected to be a representative. I'm not sure what word you are thinking of. And perhaps the concept you are trying to express only makes sense in a system where being a politician is a job?

As others have said, I think the word in English "politician" itself is neutral--neither good or bad. When someone says it out loud, you can tell if they mean negatively or positively by the context or the tone of voice their use when they say it. As for the words you mentioned, I think the more appropriate translation of a very positive, scholarly 政治家 would not be politician but rather "political scientist." The closer translation for "politician" to Chinese I would say is like (政府）官员 or maybe in some cases, depending on context, the word 政客 (I'm not familiar with this word, so I'm guessing this) Maybe you can see the distinction through this sentence: In the study of international relations, we study theories created by famous political scientists(政治家） Some of their theories explain what motivates the actions of politicians(官员、政客). Maybe in Chinese, like this? 在国际关系学，我们学习著名政治家创造的理论，其理论旨在解释政客/政府官员行为的动机是什么。

@apres moi. '政治家' may be 'statesman'; while 'politician' should be translated as '政府官员. As for '政客'', I still don't know how to translate it. Maybe there isn't a word which is equivalent to '政客'. That means I should use a sentence/phrase.

In Chinese, 政治家'zhengzhijia' is different from 政客'zhengke' in meaning. 政客 is disapproving, while 政治家 is a neutral word. But only a very great man can trully be called '政治家'.

then what about a politician who is 'neutral', let us say, we don't know whether he's good or bad. is there a name in chinese for such politicians? anyway, i think it's very subjective. as far as i know the word politician has neither negative nor positive meaning. i looked whether there are two different words for a politician in the russian language, and to my surprise, there are!