self-restraint 
noun [mass noun]
Restraint imposed by oneself on one’s own actions; self-control.The sporting code, which had been rough and ready for most of the nineteenth century, especially in Africa, began to impose more self-restraint on hunters....
- True manhood involved having a strong manly character exemplified by self-control and self-restraint.
- I didn't spend my entire time in Vegas sitting amongst gamblers and preaching the puritanical virtue of self-restraint.
Synonyms
self-control, restraint, control, self-discipline, self-mastery, self-possession, will power, strength of will, moderation, temperateness, temperance, abstemiousness, abstention, non-indulgence
informal cool
rare countenance
Derivatives
self-restrained
- Ever since he lost the election for Taipei mayor, he has been humble and self-restrained, quiet and modest, to the surprise of many.
- On one hand, we were scared; on the other hand, we were also self-restrained.
- A self-restrained judge, by contrast, will largely defer to elected politicians except in the most egregious instances, and will be reluctant to develop the meaning of clauses of the Constitution.