Where does “barking mad” come from?

barking mad (English) comes from English MAD, from Middle English mad, from Old English ġemǣd, from Proto-Germanic maidijaną, from Proto-Germanic maidaz, from Proto-Indo-European mēy- — soft, tender, dear.

barking mad (English): Completely insane

Definitions

  1. Completely insane

Ancestry of “barking mad”, step by step

barking mad traces back through two separate lines of ancestry.

via English MAD

StepLanguageWordMeaning
1EnglishMADInitialism of mutually assured destruction;...
2Middle EnglishmadMad, insane, deranged; not of sound mind;...
3Old Englishġemǣd
4Proto-Germanicmaidijanąto exchange, change
5Proto-Germanicmaidazhurt, wounded; mad, foolish; angry, enraged
6Proto-Indo-Europeanmēy-soft, tender, dear

via English barking

StepLanguageWordMeaning
1Englishbarkingpresent participle of bark; Who or that barks or...
2Middle EnglishberkyngBarking; Insulting or rude words
3Middle EnglishberkenTo bark; To grumble or whine; to utter complaints...
4Old Englishbeorcanto bark
5Proto-West Germanic*berkanto bark
Every word from Proto-Indo-European mēy-Every word from Proto-Germanic maidazEvery word from Proto-Germanic maidijaną
barking mad — Etymology, Origin & Word History | Etymology Explorer