Devotional carving kept in attic once (4)
I believe the answer is:
icon
'devotional carving' is the definition.
(religious icon)
'kept in attic once' is the wordplay.
'kept in' indicates the answer is hidden within the clue.
'ICON' can be found hidden inside 'attic once'.
(Other definitions for icon that I've seen before include "Image; celebrity" , "A religious painting or representative figure" , "Image on computer screen representing facility" , "Painting or person regarded as sacred" , "Venerated picture" .)