>Another thing I'm  curious about is the term "deórad" and the three 
>types of "outsider." These are  mentioned in Kelly's Guide, but can 
>anyone say anything more than Kelly does? 

My understanding is that the legal connotation of ‘deorad’ is an Irish
person from outside a particular kingdom (túath). They are generally, I
believe, currently resident in that kingdom (or otherwise there on
legitimate business), and therefore under the protection of (i.e.
dependent on) someone it in. For example, they may be there as a
mercenary hired in to bolster the local king's forces, or as a person
(the ‘cú glas’) who has ‘followed his wife’s arse across the border’, as
the law text says. 

The ‘murchoirthe’ is a foreigner, either from overseas or from a foreign
settlement within Ireland. Again, that person may well be in the kingdom
as a mercenary or for some other such legitimate purpose. The term
‘murchoirthe’ predates the Viking incursions. The term ‘murcoirthe’
would not apply to a slave taken from overseas, as such a person would
be a ‘mug’. The ‘deorad’ and the ‘murchoirthe’ had a reduced legal
status; the ‘mug’ had none. (The status of the ‘murchoirthe’ was less
than that of the ‘deorad’.) 

Neither the 'deorad' or the 'muirchoirthe' is an outlaw. (An outlaw
would be someone from within a particular kingdom whose illegal acts
have led to them forfeiting the protection of the law.)

Kim McCone has a discussion of the etymology of 'ambue' at Ériu 42
(1991) 41. He takes it to mean 'cow-less, worth no cows', that is,
someone who has no property in the kingdom and therefore no status. The
lack of status would also indicate that he is not the dependent of
someone with property (or profession) in the kingdom. He is just an