> og mun eigi þá á þig ráðið."
> and the attack will then not (be) on you.'

I think 'ráðið' is the past participle of 'ráða' here, rather than the
noun 'ráð' + definite article. 'ráða á e-n' "to attack someone".
Impersonal construction that would have to be paraphrased in English,
e.g. "there will be no attack on you", or with the passive "you will
not be attacked".

> brotið odd af oflæti sínu
> broken (the) tip of her arrogance (honour') (demeaned herself?)

I think so. MM & HP "My daughter was a fool to humble herself by
sleeping with you," and the translation on the proverbs page has "My
daughter Gudrun was wrong to put aside her pride and sleep with you,"

http://www.usask.ca/english/icelanders/proverbs_BNS.html

I see that Google turns up lots of examples of this expression in
Modern Icelandic.

LN