A brief explanation from the Angry Arab.

Baltaji: etymology of a Mubarak goon
The standards word used by Egyptian (and Arab) media for the armed goons of Mubarak is the word "baltaji" (بلطجي)
The word is one of those structured during Ottoman times where an Arabic word is mixed with a Turkish form: as in Qahwaji (for coffee person) or `Arbaji (a cart operator or sais--the latter is from the Arabic sa'is, probably borrowed from Crusades' times), etc. Balta is a small ax, so a baltaji (or baltachi in the Turkish pronunciation) is somebody who wields a small ax.

My dictionaries tell me that fas (or fa's?) is the Arabic for axe, that balta is the Turkish. So the word baltaji looks like pure Turkish (spelt 'baltaci' in Turkish). That -ci (or -ji) suffix is very handy - demir, 'iron', demirci, 'blacksmith'; ekmek, 'bread', ekmekçi, 'baker'.

Addendum, 4th Feb:
It appears from this posting on TGIA's blog that the plural of baltaji is baltajiyyah, Arab style, though the Egyptians do their J to G pronunciation. I believe that the Turkish plural would be baltacilar.