I've unsuccessfully googled it and looked for the meaning of this word, that I have to interpret in the following phrase: "Meine Anforderungen - nicht zu groß, günstig, mit Rollen zum Hinterherziehen, viele Seitentaschen und sie muss umhängbar sein."
The suffix -bar used in German adjectives is the about the same as -able or -ible in English, with the meaning possible, or fit.
In this case
means that you can wear or hang an object on your shoulder or around your neck. The verb is umhängen.
Usually it's referred to bags as in
Note: Though there are many "established" -bar words, but some of them (neologisms) are considered bad style (see this article).
Words with the suffix -bar are often used in descriptions of commercial products, for example
able to hang over (someone's shoulder)