Smoking is the inhaling as well as exhaling of fumes from plant materials. That's if you asked the definition.
If you ask its effect, it is an addictive act. In the long run, smoking can cause several health issues which can culminate to death.
Should you need to start smoking I will advise not to. And if you need to stop it, then my advice for you is to apply the measure, I don't know what to call it, maybe "Even and Odd Reduction Measure".
If you used to smoke 20 wraps a week, you can start reducing it by 2, and smoke 18. Then the number can further be reduced by 3, making it 15 in a week. Maintain the same 15 in the next 2 weeks. Then further reduce it this time by 2 again in the next week, and then 3 subsequent week. Maintain the current number of 10 wraps for a period of 2 more weeks or 3. Keep reducing it by 2 again this time and smoke 8 in a week. The next week you can reduce it by 3.
The idea is that reduction should be 'even' and 'odd' for every new week or month, applied to the number you used to smoke. This is ideal and works well. Complete abstinence is assured if this measure is applied religiously.