asphyxiating
as-phyx-i-at-ing
verb
Causing someone or something to stop breathing and die.
"The toxic fumes were asphyxiating the victims."
adjective
Extremely stifling or suffocating, often metaphorically for oppressive conditions.
"The heat in the small room was asphyxiating."
Thesaurus
Synonyms: dyspneic, breathless, dyspnoeic, dyspneal, dyspnoeal