someone who develops (generally inadvertently) a set pattern of doing the same thing(s) during a certain timeperiod of the day, week etc.
the opposite of someone who is spontaneous or has the ability to exhibit spontaneity.
"My father tended to be a creature of habit, especially during the weekend. For example, every Saturday morning, for as far back as I can remember, he would walk to the corner store, fetch the paper and read it at the breakfast table for approximately two hours. And every Sunday afternoon, without fail, he would take a drive out into the country, rain or shine."
Dad: son, it's when people are addicted, mostly to games where you need to bet money. it becomes a disease that needs to be treated ASAP in that particular individual. Otherwise, people can lose their financial savings. marriages, property and may even end up doing harakiri to avoid shaming those close to them.