Still cold in twilled cloth (6)

I believe the answer is:

placid

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'still' is the definition.
(I know that still can be written as placid)

'cold in twilled cloth' is the wordplay.
'cold' becomes 'C' (eg on taps).
'in' is an insertion indicator.
'twilled cloth' becomes 'plaid' (plaid is a kind of cloth. I am not sure about the 'twilled' bit.).
'c' inserted inside 'plaid' is 'PLACID'.

Can you help me to learn more?

(Other definitions for placid that I've seen before include "Calm; equable" , "Calm and not easily upset" , "Quiet and still" , "or is it an American one?" , "Still - US lake" .)

I've seen this clue in The Telegraph.

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