Letters or words, in writing or speech, that have no meaning or pattern or seem to have no meaning.

“After my father had a stroke, every time he tried to talk, it sounded like nonsense.”

An untrue statement.

“He says that I stole his computer, but that's just nonsense.”

That which is silly, illogical and lacks any meaning, reason or value; that which does not make sense.

(collective) A mixture of solid and liquid food scraps fed to pigs etc; especially kitchen waste for this purpose.

(by extension) Any disgusting or distasteful liquid.

“I cannot believe anyone could drink this swill.”

(by extension) Anything disgusting or worthless.

“This new TV show is a worthless load of swill.”