Hindu discipline (4)
I believe the answer is:
yoga
'hindu discipline' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for yoga that I've seen before include "System of exercises for bodily or mental control" , "Spiritual exercise discipline" , "Hindu system for health and relaxation" , "Hindu course of exercises and postures" , "Hindu-derived exercises" .)