adj. 1.not moving quickly 2.at a slow tempo 3.slow to learn or understand 4.(used of timepieces) indicating a time earlier than the correct time 5.so lacking in interest as to cause mental weariness 6.(of business) not active or brisk slow adv. 1.without speed (`slow' is sometimes used informally for `slowly') 2.of timepieces slow v. 1.lose velocity 2.become slow or slower 3.cause to proceed more slowly