discipline _noun 

ADJECTIVES & NOUNS

strict 
・Some parents complained about the school’s strict discipline.

strong, firm, good 
・Without good discipline in the classroom, learning suffers.

harsh
・Discipline is harsh, and can include physical punishment.

rigid
・The rigid discipline of life in a monastery was not for him.

poor 
・Problems tend to arise in families where there is poor discipline.

military
・I hated the army and the routine of military discipline.

school, classroom
・The committee looked at ways to improve school discipline.

parental
・I blame the lack of parental discipline for the way some of these kids behave.

DISCIPLINE + NOUN
problem
・The school has very few discipline problems.

VERBS

maintain, keep 
・A good teacher can maintain discipline without shouting.

enforce, impose 
・Discipline in the army is very strictly enforced.

need, require
・The children needed firm discipline.

restore
・The General wanted to restore discipline among the troops.

PHRASES

a lack of discipline
・The principal never tolerated a lack of discipline.

a breach of discipline 
・Being absent without permission was a breach of discipline.