Gets off or down from something such as a horse, motorcycle or car, or comes down from something like a tree or a mountain.
With -p, this is the "passive" or intransitive form of the original transitive verb aachan (achechaan) "takes down a large long object from a high place", which in turn is based on verb wechan (nechan) "goes down, descends, gets off".
The final "p" does not come out well in the recording.