I have this definition from Dictionary dot com.

de·ism   /ˈdiɪzəm/ Show Spelled[dee-iz-uhm] Show IPA
noun
1. belief in the existence of a God on the evidence of reason and nature only, with rejection of supernatural revelation ( distinguished from theism).
2. belief in a God who created the world but has since remained indifferent to it.

I would like to adress the idea expressed in the second part of the entry.
The God who make all things can no more be indifferent to it than an author of a novel be indiffernt to the story. It all originates with him in all it's parts and details.
Because there was nothing made before God then all that exists now comes from Him and is known about by Him. It was known about from the very beginning. This means He deliberately created everything that now exists. This contradicts the very notion of indifference.