Zaboor
The Holy Book revealed to Prophet Dawood (David), peace be on him.
Zakah
Zakah (Purifying Alms) literally means purification, whence it is used to express a portion of property bestowed in alms, as a means of purifying the person concerned and the remainder of his property. It is among the five pillars of Islam and refers to the mandatory amount that a Muslim must pay out of his property. The detailed rules of zakah have been laid down in books of Fiqh.
Zalim
Zalim is the wrong-doer, he who exceeds the limits of right, the unjust.
Zamzam
The sacred well inside Al-Haram ash-Shareef in Mecca.
Zanjabil
A special mixture that will be in one of the drinks of the people of the Paradise. See the Qur'an, Al-Insan (76:17).
Zaqqum
An extremely bitter and thorny tree that grows at the bottom of the Heelfire. See the Qur'an, Al-Isra (17:60), for example.
Zina
Zina means illegal sexual intercourse and embraces both fornication and adultery.
Zulm
Zulm literally means placing a thing where it does not belong. Technically, it refers to exceeding the right and hence committing wrong or injustice.