The one-word anagram of MOBILISES (9)

I believe the answer is:

omissible

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'the one-word anagram' is the definition.
I can't tell whether this definition defines the answer.

'of mobilises' is the wordplay.
'of' indicates anagramming the letters (the answer comes from or 'of' the letters).
'mobilises' is an anagram of 'OMISSIBLE'.

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(Other definitions for omissible that I've seen before include "not compulsory" , "Optional" .)

I've seen this clue in The Times.

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