From WordNet (r) 3.0 (2006):
bitter
adv 1: extremely and sharply; "it was bitterly cold"; "bitter
cold" [syn: piercingly, bitterly, bitingly,
bitter]
adj 1: marked by strong resentment or cynicism; "an acrimonious
dispute"; "bitter about the divorce" [syn: acrimonious,
bitter]
2: very difficult to accept or bear; "the bitter truth"; "a
bitter sorrow"
3: harsh or corrosive in tone; "an acerbic tone piercing
otherwise flowery prose"; "a barrage of acid comments"; "her
acrid remarks make her many enemies"; "bitter words";
"blistering criticism"; "caustic jokes about political
assassination, talk-show hosts and medical ethics"; "a
sulfurous denunciation"; "a vitriolic critique" [syn:
acerb, acerbic, acid, acrid, bitter, blistering,
caustic, sulfurous, sulphurous, virulent,
vitriolic]
4: expressive of severe grief or regret; "shed bitter tears"
5: proceeding from or exhibiting great hostility or animosity;
"a bitter struggle"; "bitter enemies"
6: causing a sharp and acrid taste experience;"quinine is
bitter"
7: causing a sharply painful or stinging sensation; used
especially of cold; "bitter cold"; "a biting wind" [syn:
biting, bitter]
n 1: English term for a dry sharp-tasting ale with strong flavor
of hops (usually on draft)
2: the taste experience when quinine or coffee is taken into the
mouth [syn: bitter, bitterness]
3: the property of having a harsh unpleasant taste [syn:
bitterness, bitter]
v 1: make bitter