Where does “head-scratching” come from?

head-scratching (English) comes from English head, from English -y, from Middle English -y, from Old English -iġ, from Proto-West Germanic -g, from Proto-Germanic -gaz, from Proto-Indo-European -ḱos — -y, -ic.

head-scratching (English): Confusing, perplexing, puzzling; Confusion

Definitions

  1. Confusing, perplexing, puzzling; Confusion

Ancestry of “head-scratching”, step by step

head-scratching traces back through two separate lines of ancestry.

via English head

StepLanguageWordMeaning
1EnglishheadThe part of the body of an animal or human which...
2English-yAdded to nouns and adjectives to form adjectives...
3Middle English-yDesignates an adjective, in many cases formed by...
4Old English-iġ-y, -ic
5Proto-West Germanic-gForms adjectives from nouns and verbs with a...
6Proto-Germanic-gaz-y
7Proto-Indo-European-ḱos-y, -ic

via English scratching

StepLanguageWordMeaning
1Englishscratchingpresent participle of scratch; The act or sound...
2EnglishscratchTo rub a surface with a sharp object, especially...
3Middle Englishscracchen
Every word from Proto-Indo-European -ḱosEvery word from English -yEvery word from Old English -iġ