In Arabic the words for Believer and Atheist are simple one-word terms. Mu’min and Mulhid. Even Apostate is fairly simple, Murtad. But as is consistent with the confusion of agnosticism, the glorified term for “uncertain” is uncertain.
You have the more technical term, the noun, معتنق اللاأدريّة, Mu’taniq al-la-adriyyah. This implies an adherence to uncertainty, or not knowing. But the adjective is لا أدريّ, la-adriyyah. Which literally translates to “I don’t know-er,” which I think is very apt. Instead of resorting to faux-intellectual explanations for my complicated relationship with religion, I will henceforth refer to myself as an “I don’t know-er”