Any word beginning with c that is not normally taboo but is considered (often humorously) to be so in the given context, like clitoris or cancer.
2017 March 9, “Why I don’t Use the Word ‘Craft’ and Why You Shouldn’t Either”, in Brews and Bacon:
So, the term craft is now tainted. It’s association with weird beer imbibed by stuck up people is going to be hard one to shake. Anyone with that connection in their mind is instantly going to shut down when the c-word is mentioned.