形容詞 retroactive:

1. descriptive of any event or stimulus or process that has an effect on the effects of events or stimuli or process that occurred previously
2. affecting things past
   同義詞：ex post facto, retro

ret.ro.ac.tive

adj.（形容詞）
Influencing or applying to a period prior to enactment:
有追溯效力的：影響或適用于早于頒布的時(shí)期的：
例句：
a retroactive pay increase.
應(yīng)追溯補(bǔ)發(fā)的增加工資

來(lái)源：
French rétroactif
法語(yǔ) rétroactif
from Latin retro3ctus [past participle of] retroagere [to drive back]
源自 拉丁語(yǔ) retro3ctus [] retroagere的過(guò)去分詞 [驅(qū)回]
retrô- [retro-]
retrô- [表示.后.，.向后.]
agere [to drive] * see ag-
agere [驅(qū)動(dòng)] *參見 ag-

【引伸】
ret.roac.tively
adv.（副詞）
ret.roactiv.ity
n.（名詞）