[ gruhn-dee-iz-uh m ]
/ ˈgrʌn diˌɪz əm /
a prudish adherence to conventionality, especially in personal behavior.
(lowercase) an instance of such prudishness.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Word Origin and History for grundyism
1836, from Mrs. Grundy, prudish character in Thomas Morton's 1798 play "Speed the Plow," play and playwright otherwise now forgotten, but the line "What would Mrs. Grundy say?" became proverbial.
Online Etymology Dictionary, © 2010 Douglas Harper