- to act in opposition; react
- to have reference to or influence on things done in the past
Origin of retroactfrom Classical Latin retroactus, past participle of retroagere, to drive back, reverse from retro- + agere, to drive: see act
(third-person singular simple present retroacts, present participle retroacting, simple past and past participle retroacted)
Part or all of this entry has been imported from the 1913 edition of Webster's Dictionary, which is now free of copyright and hence in the public domain. The imported definitions may be significantly out of date, and any more recent senses may be completely missing.
retro- +"Ž act