Not explicitly mentioned in Scripture but principles apply: body is a temple (1 Corinthians 6:19-20), avoid enslavement (1 Corinthians 6:12), stewardship of health. 35/100 Caution.
1 Corinthians 6:19-20: "Do you not know that your bodies are temples of the Holy Spirit, who is in you, whom you have received from God? You are not your own; you were bought at a price. Therefore honor God with your bodies." Paul's point is that the body belongs to God, and using it for practices that harm it contradicts this ownership.
Tobacco smoking is one of the clearest documented causes of preventable death — causing lung cancer, heart disease, stroke, and COPD. From a stewardship perspective, knowingly and repeatedly harming a body that belongs to God raises legitimate biblical concern.
1 Corinthians 6:12 — "I will not be mastered by anything" — addresses addiction specifically. Nicotine addiction is among the strongest known to humans. The inability to stop despite wanting to is itself spiritually relevant. Grace and Recovery: Christian smokers who want to quit should know this is not an area where shame is the appropriate response. Addiction is powerful and quitting often requires multiple attempts. Many Christian resources exist for addiction recovery including Celebrate Recovery. See also Is Caffeine a Sin?
For a thorough treatment: GotQuestions on smoking.
Questions about sin fall into two categories: things explicitly called sin in Scripture, and disputable matters (Romans 14-15) where Christians with different convictions should respect each other's consciences. Even when something isn't explicitly sinful: Does this practice reflect Christ's lordship over all of life (Colossians 3:17)? Is it beneficial — not just permissible? (1 Corinthians 10:23). Score: 35/100 Caution.
See our Is It a Sin? hub. GotQuestions and the Gospel Coalition provide thorough evangelical analysis.