Nonsense is words or behaviour with no sense in them. Talk nonsense, complete nonsense, stop this nonsense.
As a dismissal it is one of the more useful words in English, because it rejects a claim without insulting the person. Nonsense verse is a deliberate literary form — Lear and Carroll — and it works because English grammar carries meaning even when the words do not. Note that non- is simply not.
1nounnonsenseWords or behaviour with no sense in them.
“Don't talk nonsense; of course you're not too old to learn to swim.”
nonsense is meaninglessness.
Non- plus sense, from about 1610. Dutch onzin and German Unsinn are formed the same way.
From non- + sense. From non- + sense, from c. 1610. Compare the semantically similar West Frisian ûnsin (“nonsense”), Dutch onzin (“nonsense”), German Unsinn (“nonsense”), English unsense (“nonsense”).
Etymology from Wiktionary, CC BY-SA