"Strong discipline" is a phrase that refers to a state of being strict and in control. There are several synonyms for this term that can be used to convey the same idea in different contexts. One synonym for "strong discipline" is "firmness," which denotes a strong and unwavering approach to managing a situation. Another synonym that can be used is "rigor," which suggests extreme power and exactness. "Resoluteness" is also a synonym that describes unwavering commitment and determination. Lastly, "strictness" is a synonym that denotes a no-nonsense approach to maintaining order and enforcing rules. All these synonyms capture the essence of "strong discipline" in different ways and can be used interchangeably depending on the given context.