croak·er \-kə(r)\noun (-s) 1.: an animal that croaks (as a frog) 2.: any of various fishes especially of the family Sciaenidae that produce croaking or grunting noises (as certain grunts and surf fishes): as a.: atlantic croaker b.: freshwater drum c.: queenfish 3.: one that murmurs, grumbles, or complains unreasonably; especially: one that habitually forbodes evil < it didn't turn out as bad as the croakers thought > 4.[croak (I)(to kill) + -er]slang: doctor