noun
also chaperon , pl -ones also -ons
[count] US :someone (such as a teacher or parent) who goes with children on a trip or to a school dance to make sure that the children behave properly
a person in the past who went with a young unmarried woman to social events in order to make sure that the woman behaved properly
verb
also chaperon -ones or -ons; -oned; -oning
[+ obj] :to be a chaperone to or for (someone or something)