Father Ted made popular the Irish people's use of 'feck' as a non-swearing swear word. But, when I was growing up in Cornwall we had something just as good. It was the word 'tuss'.
As this short video (made in 2010) will explain, it can be a verb ('he tussed his bike up in a crash'), an adjective (he's tussing joking!') or most popularly as a noun ('He's a complete tuss').
So, if you want to swear but don't want to offend anyone, do what the Cornish do.
Problem solved.
P.s. There has been speculation that Richard James, best known as Aphex Twin, is responsible for a series of EPs released by a band called The Tuss. Richard grew up in Lanner, near Redruth and Camborne.