Infamous is an adjective used to describe something or someone as widely known of or having a reputation for something. The well-known quality is usually something sensational or generally bad. Someone can be infamous for his horrible apple pie, but is usually famous for his fantastic grape jelly.
This term may also be used to describe something or someone as evil or without morals.
Unfamous is a somewhat controversial word. It means not famous or not widely known about or respected. It is controversial in the sense that some dictionaries from the United States recognize it as a word, but most spellchecks on computers do not. European dictionaries tend to not recognize it either.
The more common formation is not famous. This can be hyphenated to made an adjective form as well. Though, one should also consider another word such as ordinary, commonplace, or normal.
Examples
Even in “Little Siberia,” as the upstate New York prison that has housed some of the state’s most infamous criminals is known, Richard Matt stood out as a man to be feared. [Fox News]
Forbes magazine three decades ago famously derided them as “callow youths” and “raiders in short pants.” Since then, Washington’s most unfamous brothers have stayed largely out of the public eye, or as invisible as two people can be when they pile up a world-class art collection, collect motion picture awards and — each — amass $4 billion fortunes. [The Washington Post]
I loved this profession and although it is not famous in the Arab world, it did already exist but was not highlighted. [Arab News]