Antagonistic criminal claiming over one grand's been stolen (8)

I believe the answer is:

inimical

I'm a little stuck... Click here to teach me more about this clue!

'antagonistic' is the definition.
(I've seen this in another clue)

I don't understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for inimical that I've seen before include "Unfriendly or unfavourable" , "Injurious - hostile" , "In claim I am strangely hostile" , "Hostile, unfavourable" , "Hostile or harmful" .)

I've seen this clue in The Independent.

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