I don't think I've ever seen/heard that word, though I gather that it might mean either blasphemous or vulgar/obscene/offensive.
I did Google it and found that there is a whole range of sweary candles for sale, and further found that it's British English, which is probably why I didn't know it.
I see that it made it into the Collins English Dictionary, the Oxford Dictionary on Lexico, Free Dictionary, Urban Dictionary, and Wiktionary, as well as the AZdictionary.