Bobbers are a type of fishing equipment that are used to keep bait and hooks at a certain depth in the water. However, there are several antonyms for the word 'bobbers' which are unrelated to fishing. These include words such as 'ascenders', 'soarers' and 'risers', all of which imply movement in an upward direction. Other antonyms for 'bobbers' include 'sinkers', 'divers' and 'descenders', which imply movement downwards. None of these words have anything to do with fishing, but instead refer to movement in a physical or metaphorical sense.