Strong’s Greek
G4089 — pikros
The entry below is Strong’s own definition (1890, public domain), and every verse where the word occurs.
πικρός
pikros — pronounced pik-ros'
perhaps from 4078 (through the idea of piercing); sharp (pungent), i.e. acrid (literally or figuratively):--bitter. see GREEK for 4078
2 occurrences in the KJV.
James 3:11
Doth a fountain send forth at the same place sweet water and bitter?
James 3:14
But if ye have bitter envying and strife in your hearts, glory not, and lie not against the truth.