The following was lifted via Google:
TAQIYYA (sometimes spelled TAQQIYYA or TAQIYA) is the duty of Muslims to lie about the beliefs, methods and objectives of Islam to non-Muslims.
Taqiyya (bad faith, deceit, contempt for the truth, false promises, evasion, deceptive moderation and crocodile tears for terrorist victims) negates any attempt at interfaith dialogue between Islam and other belief systems, because we infidels never know whether we’re being told a pack of lies.
In Islam it’s ok to lie and deceive Kafirs (infidels) because Islam is in a permanent state of war with all non-Muslims and deception is a legitimate tactic. The word or promise of a Muslim to a Kafir counts for nothing in the eyes of Allah.
So taqiyya means that the only time you can be sure that a Mullah is telling the truth is when he says he’s lying.