Single word for an idea which I have difficulty to describe in words

I am looking for an apt single word to describe the situation I am in right now:

I know a somewhat complex concept in maths, but I cannot describe it in plain english because I have difficulty to put those ideas into words - for example to communicate with others or to write them as answer in a test. I am not able to write a definition because the concept is hard for me to describe in words even though I have a vivid mental construct of it.

I came across ineffable and its synonyms, but that is not what I am looking for as we are not talking about any taboo subject.

edit:

I found the following example for ineffable or inexpressible, but those may not fit into the situation:

"the ineffable Hebrew name that gentiles write as Jehovah".

What I need:

I have an intuitive understanding of the concepts of limits and differentiability, but I cannot easily express or describe them in words. For me, those ideas are __________

Solution 1:

inchoate

Imperfectly formed or formulated : FORMLESS, INCOHERENT
misty, inchoate suspicions that all is not well with the nation m-w

Just begun and so not fully formed or developed; rudimentary. Lexico

...they can use drawing techniques to create images that were still inchoate concepts in their minds before they got them down on paper. ref.

"What are you going to write? Poetry?"
"I will not choose my form until my soul is ready. My knowledge is vast but inchoate. At the moment, I am collecting experience. ref

(Incoherent as a choice risks being understood as lacking intelligibility rather than lacking cohesion.)