morbid

Short definition from Wiktionary

Adjective

1. 1
   Of, relating to, or afflicted by disease.
2. 2
   Taking an interest in, or fixating on, unhealthy or unwholesome subjects such as death, decay, disease.
3. 3
   Suggesting the horror of death; macabre or ghoulish.
4. 4
   Grisly or gruesome.