Crossword Genius

Speaks idly of Nato, terse, never coming to a conclusion (7)

Ross

I believe the answer is:

natters

'speaks' is the definition.
The definition and answer can be both to do with communicating as well as being verbs in their -s form.
Maybe you can see a link between them that I don't see?

I cannot understand how the rest of the clue works.

(Other definitions for natters that I've seen before include "Chatters" , "Talks idly" .)

I've seen this clue in The Times.
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