غَارِبَ الاغْتِرَابِ
The back of estrangement, imagined as a mount.
الاغتراب describes being away from one's homeland and familiar surroundings. The word “back” turns an abstract condition into something that can be ridden.
This is metaphorical language, not a literal animal description. Its effect is emotional as well as decorative: the reader feels the uncertainty and exhaustion of displacement.