You might be the putative leader of your lacrosse team, even if someone else holds the title of captain. Putative means to be known as something by reputation, or assumed to be something, or generally accepted.
Every once in a while, a putative planet is reported in the news, which we get very excited about and which usually turns out to be an illusion. But in 2005, an astronomer discovered what appears to be a new planet beyond Neptune. But is this putative planet for real? There is always some doubt––something not quite official––about putative things.