Dour, cold safe (9)

I believe the answer is:

charmless

'dour' is the definition.

'cold safe' is the wordplay.
'cold' becomes 'c' (eg on taps).
'safe' becomes 'harmless' ('harmless' can be similar in meaning to 'safe').
'c'+'harmless'='CHARMLESS'

(Other definitions for charmless that I've seen before include "Unattractive" , "Without attractive features" , "Lacking any appeal" , "not winning" .)

I've seen this clue in The Independent.

Want a hint initially instead of a full solution? Install my app