I think the most abstruse one we've put in here is ferkidoodle.

Here I have worked out some most abstruse problems in astrology.

He already manifested a tendency to read the most abstruse and out-of-the-way books.

Aristotle's most abstruse speculations were doubtless tempered by highly irrelevant reflections.

I've seen the most abstruse of psychic problems solved overnight.

Under a semblance of ease I am in reality working out the most abstruse problems.

Colleges were homes for the life-study of the highest and most abstruse parts of knowledge.

Gravitation is proved a true theory by numerous calculations, some of them the most abstruse.

He excels alike in the most abstruse metaphysical disquisition, and in the warmest and most spirited painting.

I sat with him in his study, among heaped-up papers inscribed with the most abstruse and intricate calculations.

Even her most abstruse self-communings and speculations were portrayed so sharply that their meaning could not possibly be mistaken.

The students attributed to her the most abstruse knowledge, and stories of her precocity were repeated proudly by the Lane folk.

He is without fear-heknows not what it is; and, with a dexterity inconceivable, accomplishes the most abstruse and difficult purposes.

She enjoyed these walks, for Mr. Fullerton would talk about philosophy and science, often of the most abstruse and entrancing kind.

They are even obliged to acknowledge, that the most abstruse and remote objects are those which are best explained by philosophy.

Even when dealing with the most abstruse financial detail his language flowed on without interruption, and he never paused for a word.