Where does “over-optimistic” come from?

over-optimistic (English) comes from English optimistic, from English Optimist, from French optimiste, from French optimisme, from Latin optimus, from Latin Ops, from Latin oscen, from Latin opscen — to throw, reach, pierce; to hit by throwing.

Ancestry of “over-optimistic”, step by step

StepLanguageWordMeaning
1EnglishoptimisticExpecting the best in all possible ways; Allowing...
2EnglishOptimistA small centre-board sailing dinghy designed to...
3Frenchoptimisteoptimist; optimistic
4Frenchoptimismeoptimism
5Latinoptimusbest; very good
6LatinOpsearth goddess, fertility deity
7Latinoscenany bird by whose song cries augurs divined...
8Latinopscen
9Latinob-towards; against
10Latinobolusobolus (Greek coin)
11Ancient Greekὀβολόςobol, obolus, used at Athens as both a weight and...
12Ancient Greekὀβελόςa spit, rod; a horizontal line
13Ancient Greekβέλοςmissile, arrow, dart; weapon; something quickly...
14Proto-Indo-EuropeangʷélHos
15Proto-Indo-EuropeangʷelH-to throw, reach, pierce; to hit by throwing
Every word from Proto-Indo-European gʷelH-
over-optimistic — Etymology, Origin & Word History | Etymology Explorer