The phrase 'bob around' refers to an unsteady or gyrating movement of an object or person. Some of the synonyms that are close in meaning include 'bob', 'weave', 'drift around', 'sway', 'rock', 'pitch', and 'toss'. These words describe a motion that is uncertain and unsteady. They can be used interchangeably depending on the context or situation. For instance, 'bob' can describe the movement of a buoy on the sea, while 'weave' may be used to describe the movement of a snake. Similarly, 'toss' could be used to describe the movement of a ball, while 'sway' could describe the movement of a tree in the wind.