habit
noun
ˈhæbɪt 
ˈhæbɪt 
1 [countable] a thing that you do often and almost without thinking, especially something that is hard to stop doingYou need to change your eating habits.good/bad habitsHe has the irritating habit of biting his nails.It's all right to borrow money occasionally, but don't let it become a habit.I'd prefer you not to make a habit of it.I'm not in the habit of letting strangers into my apartment.I've got into the habit of turning on the TV as soon as I get home.I'm trying to break the habit of staying up too late.These things have a habit of coming back to haunt you.2 [uncountable] usual behaviourI only do it out of habit.I'm a creature of habit (= I have a fixed and regular way of doing things).3 [countable] (informal) a strong need to keep using drugs, alcohol or cigarettes regularlyHe began to finance his habit through burglary.She's tried to give up smoking but just can't kick the habit.a 50-a-day habit4 [countable] a long piece of clothing worn by a monk or nun Idioms
see force of habit at force noun