The Oxford Thesaurus An A-Z Dictionary of Synonyms - disastrousadj.

1) calamitous, catastrophic, cataclysmic, tragic, destructive, ruinous, devastating, appalling, harrowing, awful, terrible, dire, horrendous, horrible, horrifying, dreadful, fatal: There has been a disastrous earthquake which killed thousands. 2) awful, terrible, unlucky, unfortunate, detrimental, grievous, harmful: The postal strike has had disastrous effects on the mail-order business.