>So what would be the Old Irish legal term for "an outcast,
> an outlaw, someone banished or exiled, someone subjected
>to ostracism," or would there be more than one term to
>designate such persons?
Ostracism strikes me as something quite different to outlawry.
There are various words that appear to be applied to outlawry (or at
least to persons who have breached the legal duty to settle offences
according to law and are therefore subject to the bloodfeud etc.) Among
these are 'airfhócrach' and 'airfhócraid' (prescribed person, outlaw).
Perhaps the most usual term is 'dílsech'.
The phrase 'fo chaill', (hiding) in the woods', also signifies outlawry.
The Dictionary of the Irish Language suggests that 'anurrad' means
'outlaw', but I suspect it just means 'alien'.