Without a word, listen with attention (6)

I believe the answer is:

silent

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

'without a word' is the definition.
I can't tell whether this definition defines the answer.

'listen with attention' is the wordplay.
'listen' anagrams to 'SILENT'.
But, I'm not clear how this is indicated.

Can you help me to learn more?

(Other definitions for silent that I've seen before include "Not speaking" , "A continent" , "Like William Prince of Orange" , "Anagram of 7 Down" , "Making no sound" .)

I've seen this clue in the Evening Standard.

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