Where does “unforecastable” come from?

unforecastable (English) comes from English forecastable, from English able, from Middle English able, from Old French able, from Latin habilis, from Latin -ilis, from Proto-Italic -elis, from Proto-Indo-European -elis — Forms agent nouns from verbal roots.

unforecastable (English): not capable of being forecast

Definitions

  1. not capable of being forecast

Ancestry of “unforecastable”, step by step

unforecastable traces back through two separate lines of ancestry.

via English forecastable

StepLanguageWordMeaning
1EnglishforecastableCapable of being forecast; predictable
2EnglishableEasy to use; Suitable; competent; Liable to
3Middle Englishablecapable, expert, qualified, skilful, competent
4Old Frenchableable; capable
5Latinhabilisable to have/possess/maintain; having sufficient...
6Latin-ilis-ile
7Proto-Italic-elis
8Proto-Indo-European-elis
9Proto-Indo-European-lósForms agent nouns from verbal roots

via English un

StepLanguageWordMeaning
1EnglishunOne
Every word from Proto-Indo-European -lós