Term used, originally by the British police with reference to the IRA, to describe terrorists with no previously known connections to terrorism.
From the Observer: "They even won over former Irish soldiers, at least five of whom are now in jail. Many of those it recruited are so-called 'lilywhites', with no previous convictions. They are hard to trace and even harder to catch. But they are deadly and effective."
A description of a person, object, or organization that rejects any culture other than a white, middle American one. It's often accompanied by informal segregation through the use of rules or social conventions meant to exclude or discourage minorities from joining.
The lily white housing association had absolutely no minorities living in it.