1a thing that crawls or moves at a slow pace, especially an insect:the light bulb was a magnet for moths and many-legged crawlers
a tractor or other vehicle moving on an endless caterpillar track:the crawlers move space shuttles to the launch pads [as modifier]:a crawler excavator
Computing a program that searches the Internet in order to create an index of data.
2British informal a person who behaves obsequiously in the hope of gaining favour:her pleading tone surprised herself, she was no crawler