Chester41585 said:
I think FUCK is "Fornication under Consent of the King. Had something to do with the limited legalization of prostitution in the Renaissance or something.
SHIT: Ship High In Transit was a label stamped on perishable food items like tea and rice that were shipped via boat, or so I recall.
Those are both false etymologies, people trying to create an acronym from those words (or a backronym as I like to call it).
Shit and fuck, and their equivalents have existed in most languages for thousands of years.
Edit: Oops didn't realise I was the last to post, boy is my face red.