Say — say indistinctly, hiding head (5)

I believe the answer is:

utter

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'say say' is the definition.
(saying is a kind of uttering)

I don't understand the remainder of the clue.

(Other definitions for utter that I've seen before include "Make (a sound); complete" , "Speak - it's extreme" , "Speak, articulate" , "Perfect" , "Total - speak" .)

I've seen this clue in The Times.

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