It stands for "bail forfeited warrant ordered." I would consider it pretty serious. It means whoever posted the bail will lose it (unless the warrant is vacated ASAP, depending on how long ago the warrant was issued, and the circumstances, you may be able to make a a motton to get the bail money back. Unless there is a really good reason for not showing up in court, expect substantial bail to be set when the defendant returns to court, especially if he is returned involuntarily.
It means the judge forfeited the bail and asked the police to search for the defendant immediatley.
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