a sickness time is a mean of rest that buy sickness
naughtiness is disobedience. people_who is tired_should_rest. altitude_sickness is disease. naughtiness is not disobedience. morning_sickness is nausea. morning_sickness is not nausea. weekends is not time_for_rest. nap is time_of_rest. redundancy is repetition. weekends is time_for_rest.