adj.1 superfluous; not needed.
2 that can be omitted without any loss of significance.
3 (of a person) no longer needed at work and therefore unemployed.
4 Engin. & Computing (of a component) not needed but included in case of failure in another component.
Derivatives:
redundancy n. (pl. -ies). redundantly adv.
Etymology: L redundare redundant- (as REDOUND)