The story
- Proto-West Germanic · inherited from*sālīg
- Old English · inherited fromsǣliġ
- Middle English · inherited fromseely
- English todaysilly
From Middle English seely, sēlī, from Old English sǣliġ, ġesǣliġ (“lucky, fortunate”), from Proto-West Germanic *sālīg, from *sāli; equivalent to seel (“happiness, bliss”) + -y. Doublet of Seelie. The semantic evolution is “lucky” to “innocent” to “naive” to “foolish”. Compare the similar evolution of daft (originally meaning “accommodating”), and almost the reverse with nice (originally meaning “ignorant”).
Words from the same roots
Middle Englishseely all →
SeeleySeelie
Old Englishsǣliġ all →
Seelie
Etymology from Wiktionary, CC BY-SA 4.0.