Play patience (9)
I believe the answer is:
tolerance
I believe this is a double definition.
'play' is the first definition.
(both can mean room for movement in engineering)
'patience' is the second definition.
(I've seen this before)
(Other definitions for tolerance that I've seen before include "Amount of play" , "Indulgence" , "Acceptance - permitted variation in measurement" , "Willingness to accept the beliefs of others" , "Allowable variation (in a dimension)" .)