Heads could have unusual rashes, causing harm to temple (6)

I believe the answer is:

church

'to temple' is the definition.
(thesaurus)

'heads could have unusual rashes causing harm' is the wordplay.
'heads' suggests taking the first letters.
The first letters of 'could have unusual rashes causing harm' is 'CHURCH'.

(Other definitions for church that I've seen before include "Holy establishment" , "Building for religious worship" , "fold" , "House of worship" , "Place for public worship" .)

I've seen this clue in the Sydney Morning Herald.

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