Tetchy means fretfully peevish and easily upset by small things. A tetchy mood.
It suggests tiredness or illness rather than any real anger, which is what makes it forgivable. It is first recorded in Shakespeare and may well have been his word.
1adjectivetetchyFretfully peevish and easily upset by small things, in the way an overtired child or an ailing person is.
“He was tetchy for a fortnight and then apologised to everybody.”
tetchy is a quality.
The word is of uncertain origin and first appears as teachie in early quartos of Shakespeare in 1597.
Middle English
tatch — blemish
Scots
tache — blotch, fault
English, today
tetchy
Built from
unknown, first attested as teachie in the 1597 first quarto versions of Romeo and Juliet and Richard III. Perhaps coined by Shakespeare. Also variously derived from English tetch (“tantrum, fit of anger”); from Scots tache (“blotch, fault”); from Middle English tatch (“blemish”) &c. under influence from touchy.
Etymology from Wiktionary, CC BY-SA