I'm trying to.
Don't get into the habit of calling her a moron at all, ever, under any circumstances, in that case.
If you do, it will be too easy for it to just slip out at the office and seriously harm your relationship with the CEO.
At least it would be too easy for it to slip out for me.
I think you should make a point of only ever calling her by her name.
What does she do and how has she been annoying you at work? Have she and your CEO been married for a long time or was it a workplace romance?
I think they've been married for a long time. At least quite some time before he became our CEO.
As for the annoyances, it's a very long story and I'm not sure I have the strength to write it all down. What it boils down is that she is actually incompetent at what she does but that incompetence affects the rest of us because of her position within the company (she is head of sales for a department that we work with).
And yes, I have consciously focussed on avoiding the kind of thought where the word "moron" and her name are in the same sentence, paragraph, general neighbourhood, etc...
I'll live.