A verbal reservation? (9)

I believe the answer is:

reticence

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'reservation?' is the definition.
(thesaurus)

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

(Other definitions for reticence that I've seen before include "'Reserve, taciturnity (9)'" , "Tendency to be reserved in communication" , "modesty" , "Restraint" , "Quality of being sparing in communication" .)

I've seen this clue in The Globe and Mail.

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