Used where the rules aren't formally written down and are perhaps 'unspoken'
When someone breaks these rules, others show disapproval in informal ways such as refusing to speak to them, telling them off, or giving them a dirty look
Other implications of committing a criminal act include exclusion from certain occupations, placement on the violent and sex offender register, travel bans, restrictions on adoption/jury service/standing for elected office, and having to declare unspent convictions when obtaining insurance
In five multicultural societies with a large Muslim population (India, Malaysia, the Philippines, Singapore and Sri Lanka), the law permits polygamous marriages, but for Muslims only