adj. & n.
--adj.
1. looking back on or dealing with the past.
2 (of an exhibition, recital, etc.) showing an artist's development over his or her lifetime.
3 (of a statute etc.) applying to the past as well as the future; retroactive.
4 (of a view) lying to the rear.
--n. a retrospective exhibition, recital, etc.
Derivatives:
retrospectively adv.