Noun and する verb
きつえん
トーフグの社員には、喫煙する人が一人もいません。
None of Tofugu's employees smoke.
喫煙室はどこにあるかご存知ですか？
Do you know where the smoking room is?
やばーい！ちょっと面白すぎっしょ〜！何で鼻で喫煙できるなんて思っちゃったわけ？爆笑してるんですけど。
Oh my gosh! That was just way too funny! Why did you think you could smoke with your nose? I am laughing so hard right now.
If you consume smoke you are smoking.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.