noun
plural -its
a usual way of behaving :something that a person does often in a regular and repeated way [count]
If you are in the habit of doing something, you do it often or usually.
If you say that you are not in the habit of doing something, you mean that you do not do it or that you do not usually do it.
To get in/into the habit of doing something means to do something in a regular or repeated way so that it becomes a habit.
To fall/slip into the habit of doing something is to begin to do something in a regular way without realizing that you are doing it.
If you make a habit of doing something or make it a habit to do something, you do it often.
[count] :a strong need to use a drug, to smoke cigarettes, etc.
[count] :a piece of clothing worn by members of a religious group