Friends:

The Seven Qualities of an Arahat:

1: The impermanence of all constructions is perfectly seen & comprehended. 
2: The addiction & torture of all sense-desires is perfectly perceived & known..
3: His mind is only inclined towards solitude, seclusion, silent ease, and Peace...
4: The Four Foundations of Awareness are continually & perfectly established....
5: The Five Mental Abilities & Powers are thoroughly developed & consummated.....
6: The Seven Links to Awakening are utterly refined and fully accomplished.......
7: The Noble Eightfold Way is perfectly realized, acquired and all concluded.......!

By these 7 criteria, he clearly & invariably recognizes, that for him, has the
mental fermentations associated with Sense-Desire, joined with Becoming,
and grounded in Ignorance been completely & irreversibly eliminated.
Cut of at the root and like a palm tree stump never to grow again...
Mission completed. Done is what was to be done. No more of this...

More on what those gone to end, have perfected:
http://What-Buddha-Said.net/drops/III/Awareness_Sati.htm
http://What-Buddha-Said.net/drops/III/Five_Abilities_Summary.htm
http://What-Buddha-Said.net/drops/III/Leading_to_Enlightenment.htm
http://What-Buddha-Said.net/drops/II/The_Way.htm

http://What-Buddha-Said.net/drops/IV/Perfectly_Enlightened.htm

http://What-Buddha-Said.net/drops/Best_among_Gods_and_Men.htm


Arahat Bhikkhu                                     & Bhikkhuni

Source: The Exhaustive Speeches by the Buddha. Digha Nikaya 34
http://www.pariyatti.com/book.cgi?prod_id=25103
http://www.accesstoinsight.org/canon/digha/index.html