IPA: //ˈkræbər//
KK: /ˈkræbər/
A person or a boat that catches crabs, typically for food or commercial purposes.
The crabber returned with a full catch after spending the day on the water.
Crabber is formed from "crab" (from Old English "crabba", meaning a type of crustacean) and "-er" (meaning a person who). A crabber is a person who catches or collects crabs.
Think of someone who catches crabs — the word 'crabber' combines the name of the crustacean with '-er' to indicate a person involved in that activity.