Where does “thickheadedness” come from?

thickheadedness (English) comes from English thickheaded, from English headed, from English head, from English -y, from Middle English -y, from Old English -iġ, from Proto-West Germanic -g, from Proto-Germanic -gaz — -y, -ic.

thickheadedness (English): stupidity

Definitions

  1. stupidity

Ancestry of “thickheadedness”, step by step

thickheadedness traces back through two separate lines of ancestry.

via English thickheaded

StepLanguageWordMeaning
1Englishthickheadedstupid, obtuse or dumb
2EnglishheadedOf a sheet of paper: having the sender's name,...
3EnglishheadThe part of the body of an animal or human which...
4English-yAdded to nouns and adjectives to form adjectives...
5Middle English-yDesignates an adjective, in many cases formed by...
6Old English-iġ-y, -ic
7Proto-West Germanic-gForms adjectives from nouns and verbs with a...
8Proto-Germanic-gaz-y
9Proto-Indo-European-ḱos-y, -ic

via English Ness

StepLanguageWordMeaning
1EnglishNessAn Ulster princess and the mother of Conchobar mac Nessa and Findchoem in the Ulster Cycle of Irish mythology. Daughter of Eochaid Sálbuide. Also the mother of Cormac Cond Longas by incest with Conchobar mac Nessa
2Middle Englishnesse
3Old Englishnæsnot, not at all; not; first/third-person singular...
4Proto-Germanicnasjąfoothill; headland; cape
5Proto-Indo-Europeannéh₂snose
Every word from Proto-Indo-European -ḱos