Descriptive of a computer microprocessor that is able to process high-level, complex instructions. Complex instructions require fewer individual instructions in order to accomplish a single task, which makes programming less time-consuming. However, additional processing time is required for the processor to decode and execute the instructions. CISC-based processors require complex arrays of large numbers of transistors, which makes design difficult. A common alternative is a RISC-based processor. See also Reduced Instruction-Set Computing.