Where does “underdressed” come from?

underdressed (English) comes from English underdress, from English dress, from English -ing, from Old English -ing, from Old English -tūn, from Old English tūn, from Proto-West Germanic tūn, from Proto-Germanic tūną — smoke; mist, haze.

underdressed (English): Insufficiently dressed, "as" for cold weather;...

Definitions

  1. Insufficiently dressed, "as" for cold weather;...

Ancestry of “underdressed”, step by step

underdressed traces back through two separate lines of ancestry.

via English underdress

StepLanguageWordMeaning
1EnglishunderdressTo dress in insufficiently warm clothes; To dress...
2EnglishdressTo fit out with the necessary clothing; to...
3English-ingUsed to form gerunds, a type of verbal nouns,...
4Old English-ingForming nouns from verbs, indicating action,...
5Old English-tūnhomestead, village, town
6Old Englishtūnenclosure, yard; place; dwelling
7Proto-West Germanictūnfence
8Proto-Germanictūnąfence; enclosure
9Gaulishdunumfort; hill, hillfort
10Proto-Celticdūnomstronghold, rampart
11Proto-Indo-Europeandʰewh₂-smoke; mist, haze

via English dressed

StepLanguageWordMeaning
1Englishdressedsimple past tense and past participle of dress;...
Every word from Proto-Indo-European dʰewh₂-