Uncertain. Perhaps derives from the Hungarian bocskor, meaning a certain sole-less footwear used by Balkanic shepherds, in Romanian called opincă. Often considered to have originally meant "man without a country" in Hungarian, but this is probably not true. Hungarians on the other hand believe the word may have instead come from Romanian or Slavic. Another less likely theory suggests the verb boscorodi ("to grumble, murmur").
The word could also originate from Turkic bozkır meaning steppe.