panglossian

adjective

1. characterized by or given to extreme optimism, especially in the face of unrelieved hardship or adversity.

adj.“optimistic” (usually ironic or disparaging), 1831, from French Panglosse, name of the philosopher and tutor in Voltaire’s “Candide” (1758), from pan- (see pan-) + Greek glossa, literally “tongue” (see gloss (n.2)).