To be "a man among men" implies that a person is remarkable and stands out as different. The phrase may also denote that a man is accepted in society among contemporaries, peers or within a community. Since it may have two opposing meanings, the phrase is therefore a contranym.
Stating that a person is a man among men may denote in one sense that the person is exceptional, or in another sense that he is unexceptional. Mark Twain uses this phrase to convey the former in "The American Claimant." He writes, "I am a man among men, on an equal footing with Tom, Dick and Harry." John Milton, on the other hand, conveys a sense of being exceptional in "Paradise Lost, Book III," by writing, "And be thy self Man among men on Earth."