discipline has 13 distinct synonyms spread across 4 of its 7 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. Its one recorded opposite is indiscipline.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
a branch of knowledge
“in what discipline is his doctorate?”
a system of rules of conduct or method of practice
“he quickly learned the discipline of prison routine”
the trait of being well behaved
“he insisted on discipline among the troops”
the act of disciplining
“the offenders deserved the harsh discipline they received”
punish in order to gain control or enforce obedience
“The teacher disciplined the pupils rather frequently”
Synonyms, antonyms and the broader and narrower relations for discipline come from Princeton University’s WordNet. Full sources and licences.