Definition
Unruly means resistant to rule — literally so, since it is built straight from 'rule' itself. An unruly thing will not be governed, ordered or held in line: a crowd, a class of children, a head of hair, a debate that keeps boiling over. The word carries a hint of energy rather than malice — unruly things are lively and self-willed, not evil — but they exhaust whoever is trying to keep order. Whatever structure you impose, an unruly subject keeps bulging back out of it.
Examples
Collocations
an unruly crowd·unruly behaviour·unruly hair·an unruly mob·an unruly class
Synonyms
disorderly·unmanageable·rowdy·undisciplined·wayward
Antonyms
orderly·docile·compliant·disciplined
Word family
unruliness (noun)
In TOEFL & IELTS
A vivid descriptive adjective for Speaking and Writing about crowds, behaviour and even hair. Strong collocations: an unruly crowd / mob / class / child, and the fixed 'unruly hair'. Note the spelling — no 'e' before the -ly (unruly, not unrulely) — and the stress on the long middle syllable: un-ROO-lee.