1. 
[syn: awful, dire, direful, dread(a), dreaded, dreadful, fearful, fearsome, frightening, horrendous, horrific, terrible]
The Collaborative International Dictionary of English v.0.48:
Direful \Dire"ful\, a. [Dire + -ful.]
   Dire; dreadful; terrible; calamitous; woeful; as, a direful
   fiend; a direful day. -- Dire"ful*ly, adv. --
   Dire"ful*ness, n.
   [1913 Webster]
WordNet (r) 3.0 (2006):
direful
    adj 1: causing fear or dread or terror; "the awful war"; "an
           awful risk"; "dire news"; "a career or vengeance so
           direful that London was shocked"; "the dread presence of
           the headmaster"; "polio is no longer the dreaded disease
           it once was"; "a dreadful storm"; "a fearful howling";
           "horrendous explosions shook the city"; "a terrible
           curse" [syn: awful, dire, direful, dread(a),
           dreaded, dreadful, fearful, fearsome,
           frightening, horrendous, horrific, terrible]