Crossword Genius

Cold gas, natural (9)

Ross

I believe the answer is:

heartless

'cold' is the definition.
(thesaurus)

'gas natural' is the wordplay.
'gas' becomes 'He' (chemical symbol for helium).
'natural' becomes 'artless' (I've seen this before).
'he'+'artless'='HEARTLESS'

(Other definitions for heartless that I've seen before include "hard?" , "Scrooge was" , "Lacking all feelings" , "Lacking feeling through cardiac deficiency" , "That's very cruel" .)

I've seen this clue in The Times.
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