Something that floats, or a person who floats or wanders without purpose.
From the root 'float' (from Old English 'flotian') plus the agent suffix '-er' (one who does something). The term developed to describe both objects that float and people without settled lives.
A 'flotter' can mean a fishing float or buoy, but it's also Victorian slang for a vagrant—you're describing the object and the person both by their tendency to move aimlessly and without anchoring!
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