(1) Supernatural power. 
(2) Illusion. Whatever one sees is not there in reality. 
(3) Trick. 
(4) Siddhaantists say that Maayaa is the clay (material cause or proximate cause, Upaadaan Kaaran), Shakti is the potter's wheel (the instrumental, or concurrent, or expedient, cooperating cause, or the Sahakaaree Kaaran), and God is the maker (efficient cause or Naimittik Kaaran) of this world and beings. While God is A-Kaaran - there is no cause for Him, other than Him.
(5) Another name of Brahmaa's Shakti whose Beej Matra is Hreeng, the immediate or active power or Shakti of Creation.

Maayaa's literal meaning is "Not this". Maayaa is responsible for the illusion that the phenomenal world is a reality. In A-Dwait Vedawnt Maayaa is a veil to hide the truth, unitary Self, the Cosmic Spirit, also known as Brahm. A-Dwait Philosophy holds Brahm is the only Reality, hence Maayaa cannot be true. At the same time Maayaa can not be untrue because it causes the material world to be seen. Hence Maayaa is considered as indescribable. Maayaa has two functions to perform - one is to cover up Brahm and hide it from our mind; and the other is to present the material world instead of Brahm. Let us consider an illusion of a rope being mistaken for a snake in darkness. Once the true knowledge of the rope is perceived, the illusion of the rope gets destroyed. Similarly Maayaa also gets destroyed for a person when he has perceived Brahm which is the only Reality. When Maayaa is regarded as true, it becomes the magical power of the Supreme Lord to create and rule the world. Maayaa is like God's servant. God is not affected by the impiety of Maayaa, just as a magician is not cheated by his own magical powers. While God is bliss, individuals are under the spell of Maya. Hence their miseries and sufferings. Ahankaar (ego- consciousness) and Karm are said to be the binding forces of Maayaa.

Shankar, though claiming to follow the Upanishad, has put out his own theory of non-Dualism, in which he states that only Brahm is real and Prakriti (the sense and everything that the senses perceive) is Maayaa. By Maayaa, he means that which is unreal or which is an illusion. He includes man's mind as part of Prakriti - Maayaa. There are two things to be said about this doctrine - (1) First, this doctrine is not founded in Upanishad, and he is not supported in his meaning of the words Maayaa by Upanishad; (2) Second, his assertion that Prakriti including mind is unreal poses a serious problem. Because if mind is unreal then Shankar is rendered incapable of knowing the reality - his mind is also an illusion.
[Aangiras, p 286]

In Shaiv Siddhaant, Maayaa is the First Cause and an expression of God's Will (Ichchhaa). Maayaa is dependent on God and not dynamic on its own accord and this character is Asat (non-being). Maayaa is the innate power of the Shakti (Parigraha-Shakti). Shiv is its hypostasis and its cause. Shiv’s Will is its immediate cause. Maayaa is an object that has a function. An object and the knower are two different entities. The knower may not know everything about an object. That is not the case with Shiv who activates Maayaa which produces the object. Shiv is the knower and knows the object to its fullness, since Shiv is the Creator of the object through Shakti. The Divine Will, prior to Maayaa, is the knowing Consciousness and determines the object's existence, structure and function. Shiv is the agent; Shakti is the instrument; Maayaa is the object.