Acclimatise (9)
'acclimatise' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for attune that I've seen before include "Bring into harmony" , "Become receptive (to)" , "Harmonise or adapt to idea or music" , "Acclimatise" , "Orient" .)
'acclimatise' is the definition.
(thesaurus)
This is all the clue.
(Another definition for habituate that I've seen is " Get used to".)