not directly controlled by or connected to a computer or to the internet 未联机的；未连线的；脱机的；离线的
Idioms
take something offline
to talk about something on a later occasion, perhaps because it does not interest the other people who are present at a meeting 以后再谈（可能因会议上其他人对该话题不感兴趣） Could you two take that offline so we can move onto the other items on the agenda? 你们二位以后再谈这个话题好吗？这样我们就可以继续讨论议程上的其他事项了。