Yoga pose reformed louts (5)
I believe the answer is:
lotus
'yoga pose' is the definition.
(I've seen this in another clue)
'reformed louts' is the wordplay.
'reformed' indicates an anagram.
'louts' is an anagram of 'LOTUS'.
(Other definitions for lotus that I've seen before include "reason for indolence" , "One of the lilies" , "Mythical plant inducing languor" , "Indian waterlily" , "TREE" .)