Compulsive bosses I've sent crazy (9)

I believe the answer is:

obsessive

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'compulsive' is the definition.
('obsessive' can be a synonym of 'compulsive')

I cannot understand how the rest of the clue works.

Can you help me to learn more?

(Other definitions for obsessive that I've seen before include "Unable to let go" , "Compulsive, fixated" , "Showing continual preoccupation" , "Continually preoccupied" , "Under a strong compulsion" .)

I've seen this clue in The Independent.

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