Abbott-Smith Manual Greek Lexicon
πικρός (G4089)
2 πικρός , -ά, -όν (poët. in cl.), [in LXX chiefly for מַר ;] sharp , pointed . sharp to the senses; of taste, bitter : opp. to γλυκύ , Ja 3:11 ; metaph., harsh , bitter : Ja 3:14 .
G. Abbott-Smith, A Manual Greek Lexicon of the New Testament (1922) — public domain