Source : Webster's Revised Unabridged Dictionary (1913)

Baleful \Bale"ful\, a. [AS. bealoful. See {Bale} misery.]
   1. Full of deadly or pernicious influence; destructive.
      ``Baleful enemies.'' --Shak.

            Four infernal rivers that disgorge Into the burning
            lake their baleful streams.           --Milton.

   2. Full of grief or sorrow; woeful; sad. [Archaic]

Source : WordNet®

baleful
     adj 1: deadly or sinister; "the Florida eagles have a fierce
            baleful look" [syn: {baneful}]
     2: threatening or foreshadowing evil or tragic developments; "a
        baleful look"; "forbidding thunderclouds"; "his tone
        became menacing"; "ominous rumblings of discontent";
        "sinister storm clouds"; "a sinister smile"; "his
        threatening behavior"; "ugly black clouds"; "the situation
        became ugly" [syn: {forbidding}, {menacing}, {minacious},
        {minatory}, {ominous}, {sinister}, {threatening}, {ugly}]