WordWeb Online

1. Detrimental to health
   - insalubrious, unhealthy
    
2. Not sanitary or healthful
   "unhealthful open sewers";
   - unsanitary, insanitary
    
3. Detrimental to good health
   "unhealthful air pollution"; "unhealthful conditions in old apartments with peeling lead-based paint"

See also: crippling, cytopathogenic, disabling, incapacitating, infected, infective, morbific, nonmedicinal, pathogenetic, pathogenic, septic, toxic, unhealthy, unhygienic, unmedical, unmedicative, unmedicinal, unwholesome

Antonym: healthful