nonsense

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.

To make nonsense of;

To attempt to dismiss as nonsense; to ignore or belittle the significance of something; to render unimportant or puny.

To joke around, to waste time

Resulting from the substitution of a nucleotide in a sense codon, causing it to become a stop codon (not coding for an amino-acid).

Nonsensical

An emphatic rejection of something one has just heard and does not believe or agree with.