nonsense

1. 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.

2. An untrue statement.

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

3. That which is silly, illogical and lacks any meaning, reason or value; that which does not make sense.
4. Something foolish.
5. A type of poetry that contains strange or surreal ideas, as, for example, that written by Edward Lear.
6. A damaged DNA sequence whose products are not biologically active, that is, that does nothing.

1. To make nonsense of;
2. To attempt to dismiss as nonsense; to ignore or belittle the significance of something; to render unimportant or puny.
3. To joke around, to waste time

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

interjection

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