1) Cerebration 2) Higher cognitive process 3) Mentation 4) Notion 5) Reasoning 6) The exercise of the intellect 7) Thinking 8) Thought Found on https://www.crosswordclues.com/clue/intellection
• (n.) A mental act or process; especially: (a) The act of understanding; simple apprehension of ideas; intuition. Bentley. (b) A creation of the mind itself. Found on http://thinkexist.com/dictionary/meaning/intellection/
In`tel·lec'tion noun [ Latin intellectio synecdoche: confer French intellection .] A mental act or process; especially: (a) The act of understanding; simple apprehension of ideas; intuition. Bentley . (b) A creation of the mind itself. Hickok. Found on http://www.encyclo.co.uk/webster/I/74
the action or process of understanding; the exercise of the intellect; reasoning. · a particular act of the intellect. · a conception or idea as the result of such an act; notion; thought. Found on https://www.infoplease.com/dictionary/intellection