'Non sequitur' definitions:

Definition of 'non sequitur'

(from WordNet)
noun
A reply that has no relevance to what preceded it
noun
(logic) a conclusion that does not follow from the premises

Definition of 'Non sequitur'

From: GCIDE
  • Non sequitur \Non seq"ui*tur\ [L., it does not follow.] (Logic) An inference which does not follow from the premises. [1913 Webster]

Synonyms of 'non sequitur'

From: Moby Thesaurus