Bullfighter endlessly changing direction, one twisting around (7)

I believe the answer is:

tornado

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'bullfighter' is the definition.
Although both the answer and definition are singular nouns, I don't understand how they can define each other.

I don't understand the remainder of the clue.

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(Other definitions for tornado that I've seen before include "Whirling storm" , "Violent swirling wind" , "Whirling windstorm" , "Donator (anag.)" , "Terrible current" .)

I've seen this clue in The Independent.

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