Like a quiet snake (3)

I believe the answer is:

asp

'snake' is the definition.
(asp is a kind of snake)

'like a quiet' is the wordplay.
'like' becomes 'as'.
'a quiet' becomes 'p' (music symbol for 'piano', ie soft or quiet).
'as'+'p'='ASP'

(Other definitions for asp that I've seen before include "Small poisonous snake" , "Snake of the Nile" , "Cold-blooded killer" , "Snake found in spa" , "Pa's Cleopatra's killer" .)

I've seen this clue in The Irish Independent.

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