What is Crawler?

Crawler definition and meaning on Dictionary terms:

a person or thing that crawls.
Also called crawler tractor. any of various large, heavy vehicles or machines that are propelled on endless belts or tracks, especially as used in construction.
Often crawlers. a garment with long pants, short sleeves or suspender straps, and sometimes feet for a baby who does not yet walk.
Australian Slang. sycophant.