See nonsense in Webster's New World College Dictionary
noun
words or actions that convey an absurd meaning or no meaning at all
things of relatively no importance or value; trivialities
impudent, foolish, or evasive behavior
adjective
designating or of syllables or words constructed of sounds or symbols arranged arbitrarily so as to have no meaning
of or designating verse, poetry, or other literary composition consisting of words or syllables that convey an absurd meaning or no meaning at all
interjection
how foolish; how absurd: an exclamation of impatience, contradiction, contempt, etc.
See nonsense in American Heritage Dictionary 4
(nŏnˈsĕnsˌ, -səns)
noun
Words or signs having no intelligible meaning: a message that was nonsense until decoded.
Subject matter, behavior, or language that is foolish or absurd.
Extravagant foolishness or frivolity: a clown's exuberant nonsense.
Matter of little or no importance or usefulness: a chatty letter full of gossip and nonsense.
Insolent talk or behavior; impudence: wouldn't take any nonsense from the children.
adjective
Genetics Of or relating to a mutation in a structural gene that changes a nucleotide triplet into a stop codon, thus prematurely terminating the polypeptide chain during protein synthesis.