Make indebted; constrain (6)
I believe the answer is:
oblige
I believe this clue is a double definition.
'make indebted' is the first definition.
(I've seen this in another clue)
'constrain' is the second definition.
(I know that constrain is a kind of oblige)
(Other definitions for oblige that I've seen before include "Perform a service for (someone)" , "Perform a favour for" , "Compel (someone to do something)" , "Compel - do favour to" , "Do favour or coerce" .)