Using sufficient instead of enough as a noun is clumsy and sounds old-fashioned, as in Thank you, but I’ve had sufficient, and even as an adjective sufficient almost always sounds stiffer and more Formal than enough, as in I have sufficient information to write the article, as does insufficient for a negative: compare We don’t have enough time to reach the station with We have insufficient time to reach the station. In any case, use either sufficient or enough, depending on the level you seek, but don’t use both together, as in This flour is sufficient enough for today’s baking. Sufficient is sufficient. Enough’s enough. See AMPLE ENOUGH.
