[name_m]How[/name_m] usable would you say [name_m]Esker[/name_m] is as a boys name?
I think it’s likely to be mistaken for [name_f]Esther[/name_f], but I don’t think it’s unusable.
I think it’s usable but it’s very unfamiliar and might be misheard as [name_f]Esther[/name_f].
I really like it. I think its perfectly useable.
Thanks for the comments, everyone 
Sounds very similar to [name_f]Esther[/name_f], and is reminiscent of both [name_m]Edgar[/name_m] and [name_m]Oskar[/name_m], but it has an appealing sound. I looked it up and it also has an interesting meaning: Esker - Wikipedia
I can definitely see the appeal!
It’s usable, imo.