optimist

noun

1. A person who expects a favourable outcome.

   “We are becoming as a nation, as a world, indeed, atom-conscious. Many of us are already afflicted with atomphobia, though so far it has manifested itself only in a mirage of autoaeromotive discs and a war of words between chronic optimists and empirical pessimists concerning civilization’s probable future.”

2. A believer in optimism.
3. A small centreboard sailing dinghy designed to train and introduce young children into sailing.