Lie about attitude (6)
I believe the answer is:
repose
'lie' is the definition.
(reposing is a kind of liing)
'about attitude' is the wordplay.
'about' becomes 're' ('re' means regarding or about).
'attitude' becomes 'pose' (attitude can mean a pose or stance).
're'+'pose'='REPOSE'
(Other definitions for repose that I've seen before include "Lie at rest" , "peace" , "State of tranquillity" , "calm" , "place" .)