not think of (something)
1. To not conceive of an idea. I didn't think of that—good idea! When I asked him why he didn't just use his spare key, he said he just hadn't thought of it.
2. To not consider something in a particular way. I know many people consider her response to be disingenuous, but I don't think of it that way. He doesn't think of it as fraud, but rather as recording profits "creatively."
3. To not remember something. Sorry, I didn't think of the milk when I was at the store.