My Dad was a churchwarden, devout christian and a "believer" and rarely, if ever, did I ever hear him use a bad word.
Somewhat Victorian in views and attitudes.
As a Devonian, he did use "bu**er" but more as a term of endearment than anything nasty.
One evening, playing Scrabble, he turned his tiles towards me and said "I haven't a clue what to do with these without upsetting Mum".
He had, I promise, U N T F C K C on display.
I suggested "tun" - he was most grateful.