1.  difficult;  hard;  troublesome;  complicated;  serious (disease, problem, etc.)
2.  impossible;  unfeasible
euphemistic
3.  fussy;  particular;  fastidious;  hard to please;  displeased
4.  gloomy;  glum;  sullen;  serious (look)
5.  dirty;  unclean;  filthy;  detestable
6.  unpleasant;  uncomfortable;  creepy;  spooky