Smokers who smoke at a low rate, e.g., 1-5 cigarettes per day. An estimated 10-20% of all smokers are chippers. Also know as social smoker or a periodic smoker.
"Chipper" is a word used to describe people who use tobacco at low levels, often socially, without becoming addicted and/or suffering from withdrawal symptoms. The term was originally used in reference to heroin users who didn't become addicted to the drug.
A chipper is an occasional tobacco smoker who isn't subject to the heavy level that is typical of addicted smokers. Such occasional users of tobacco are also dubbed social smokers which is similar in meaning to social drinker. Chippers are given as an example in The Tipping Point; if chippers begin smoking above a certain threshold (or tipping point), then they will develop regular cravings and become addicted.