I can define God as the first cause. Why? because I want to.
But this definition is personal. Most of the theists have their own personal definition of God.
Some says God is love. ( I dont understand though if god is love why confuse others by calling love as God? Is it so hard to write one letter extra (love) instead of God )
Well whatever, the point is there is no objective definition of God.... So from an objective view the word God is obsolete.