1600-1700 Probably from prig ‘showy man’(17-19 centuries), perhaps from prig ‘tinker, thief’(16-19 centuries)
Examples
EXAMPLES FROM THE CORPUS
Hugh was a City prig of exemplary emotional repression.
I became an insufferable prig, too.
I used to be such a smug little prig.
They informed him that he was a prig.
Yet he was not a prig.
someone who behaves in a morally good way and shows that they disapprove of the way other people behave – used to show disapproval: Don’t be such a prig! It’s only a bit of harmless fun!—priggish adjective: a rather priggish, old-fashioned man—priggishness noun [uncountable]