offline Syllabification: (off·line)Pronunciation: /ˈôfˈlīn, ˈäf-/ ComputingDefinition of offline adjective not controlled by or directly connected to a computer or external network. adverb (also off line) while not directly controlled by or connected to a computer or external network. with a delay between the production of data and its processing. offline in other Oxford dictionaries Definition of offline in the British & World English dictionary