Suffocated is a term used to describe the act of being deprived of oxygen, usually through smothering or choking. Smothered is a synonym for suffocated, and it is defined as being deprived of air or oxygen by having something heavy placed on top of one's body. Suffocation can be caused by a variety of factors, including drowning, strangulation, and even being buried alive. Suffocation can be fatal if not treated quickly.