alighten
Alighten (verb) means to get down from something, such as a horse or a vehicle.
Etymology
Came into English from Middle English alighten, which arose from a merger of two Old English words: ālīhtan (“to alight, dismount”), formed from the prefix ā- (compare Gothic ??- (us-), German er-, originally meaning "out") and līhtan (“to alight”); and ġelīhtan (“to alight, approach, come, come down, dismount”). It can also be analysed as alight + -en.