Definition:
"Smoking" can be used in different ways, but it generally refers to the act of producing smoke or the process of burning something. It can describe something that is giving off smoke or refer to the activity of inhaling smoke from tobacco or other substances.
As an Adjective:
When used as an adjective, "smoking" describes something that is emitting smoke. For example, you might say, "The smoking fireplace filled the room with warmth and scent."
As a Noun:
When used as a noun, "smoking" refers to the act of inhaling smoke from tobacco or other substances. For example, "He went outside for a smoke," meaning he went outside to smoke a cigarette.