I see no word like what you spelled in my Yiddish dictionaries. Yiddish uses vov for the sound oo, unlike Hebrew kholom with the dot above the vav, pronounced o or oh. I think you mean "beys, komets-alef, kuf" (bok) which means "billy goat" (he-goat). I've never heard it used about a person, but I suppose it could mean someone who is dorky or stubborn. BTW, it is not a loan-word, just Yiddish from the Germanic side, related to "buck" (adult male of several species of animals) in English. Compare animals related to antelopes, e.g., blackbuck, reedbuck, bushbuck. Between alternate spellings and other species, there are about 20 species whose names end in "bok."