1. difficult to understand; obscure or complex
Usage: formal

Examples

• The professor’s abstruse theories confused most of the students.
• She found the mathematical concepts too abstruse to grasp quickly.
• The philosopher’s abstruse writings require careful study.
• His abstruse explanation left the audience bewildered.
• The legal document was filled with abstruse terminology.
• Even experts struggled with the abstruse technical manual.