Threatening to remove voluminous parts (7)

I believe the answer is:

ominous

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

'threatening' is the definition.
(I know that threatening can be written as ominous)

I don't understand the remainder of the clue.

Can you help me to learn more?

(Other definitions for ominous that I've seen before include "Not looking good, dark clouds ahead" , "Minatory, trouble coming" , "Looking like trouble coming" , "Inauspicious" , "Portentous" .)

I've seen this clue in the Evening Standard.

Want a hint initially instead of a full solution? Install my app