Extended Strong's Greek Lexicon (Abbott-Smith based)
bitterness
Usage: πικρία, -ας, ἡ (πικρός), [in LXX chiefly for מַר and cognate forms ;] bitterness; __(a) of taste (Arist., Jer.15:17, al.); __(b) metaphorically, of temper, character, etc.: Rom.3:14 (LXX), Eph.4:31; ῥίζα πικρίας, Heb.12:15; χολὴ π., a malignant disposition, Act.8:23.† (AS)