:: COMPARE ::
The short answer
Optimism expects a good outcome and can still read the evidence. Delulu assumes an outcome the evidence doesn't support — and, in its modern self-aware use, knows it and proceeds anyway.
Side by side
| Aspect | Delulu | Optimism |
|---|---|---|
| Evidence | Ignored | Weighed |
| Self-aware? | Usually, now | Yes |
| Tone | Playful, absurd | Sincere |
| Started as | An insult | A virtue |
What each one means
Delulu is a playful shortening of 'delusional', used for someone whose beliefs — about a crush, a celebrity, a career, an outcome — run well ahead of the evidence — and now often worn proudly, as a badge of stubborn optimism.
Full definition of Delulu →The contrast above sets out how Optimism differs from Delulu on the points that actually matter.