A euphemism for describing someone who lacks morals or changes their morals to suit their needs, typically a shady businessman, graft politician or one involved in illegal activities.
Tom: Doesn't Dick have a problem selling drugs to kids?
Harry: Nah, he's businessman... plus it helps that he's 'morally ambiguous.'
Tom: Oh, cool. Wanna burn one?
Euphemism for homosexuals used by conservatives
John: Wow that Elton John is really morally ambiguous
George: Ya what a homo