The FCC has regulations on broadcast TV, put in place because the airwaves are a limited resource and they want TV to be generally viewable without great offense. So no nudity and no swearing.

There actually isn’t an official list of words. Instead it’s a policy on offensiveness.[1] Also, this applies to all broadcasts. So radio as well as broadcast TV. It is, however, limited by time of day. Swear away between 10pm and 6am.

Generally, it is consider that profane swears are: fuck (and derivations like motherfucker), shit (and derivations), and slang terms for penis or vagina are all “profane”. “Damn” has lost it’s place on that list and you can use obvious replacement words for fuck or shit, like “shoot” or “frak”. People can use “dick”, as long as they are not referring to a penis (and yes, comedians can get very strong in implication that they really mean penis, as long as they can plausibly say that “dickweed” is a plant, or whatever.)

You should note that none of this applies to cable TV. Although, as a nod towards retaining a general audience, those profane swears really aren’t used outside of that same 10pm to 6am period—although it gets complicated with the time zones in the U.S., so you might hear “shit” at 7:05pm on the West Coast. Really, only pay channels say fuck it and play whatever rating at whatever hour.

Footnotes