From Longman Dictionary of Contemporary Englishall clearˌall ˈclear, all-clear noun → the all clear
Examples from the Corpus
all clear• Which is correct is not at all clear.• It is not at all clear that physical distances or times can realistically be said to have this property.• It is not at all clear that such absurdly tiny scales have any physical meaning whatever.• What is not at all clear, however, is the way one should adjudicate the differences.• But it was not at all clear that Clinton could win the election.• Indeed, it was not at all clear that Eisenhower and Khrushchev could control the hardliners in their own countries.• But at the time, of course, this was not at all clear. 