Where does “undefatigable” come from?

undefatigable (English) comes from English defatigable, from Latin defatigatus, from Latin dēfatīgō, from Latin dē-, from Latin dē, from Latin post, from Latin poste, from Proto-Italic posti — afterwards, post; by, at.

undefatigable (English): Obsolete form of indefatigable

Definitions

  1. Obsolete form of indefatigable

Ancestry of “undefatigable”, step by step

undefatigable traces back through two separate lines of ancestry.

via English defatigable

StepLanguageWordMeaning
1EnglishdefatigableEasily tired or wearied; capable of being...
2Latindefatigatusexhausted; discouraged
3Latindēfatīgōto tire out or exhaust
4Latindē-of; from
5Latinof; concerning; about
6Latinpostbehind; after, since, besides, except; behind,...
7Latinposteablative singular of postis
8Proto-Italicpostibehind, after
9Proto-Indo-Europeanpóstiafter
10Proto-Indo-Europeanpósafterwards, post; by, at

via English un

StepLanguageWordMeaning
1EnglishunOne
Every word from Proto-Indo-European pósEvery word from Latin dē-Every word from Proto-Indo-European pósti
undefatigable — Etymology, Origin & Word History | Etymology Explorer