Strong’s Greek
G4090 — pikros
The entry below is Strong’s own definition (1890, public domain), and every verse where the word occurs.
πικρῶς
pikros — pronounced pik-roce'
adverb from 4089; bitterly, i.e. (figuratively) violently:--bitterly. see GREEK for 4089
2 occurrences in the KJV.
Matthew 26:75
And Peter remembered the word of Jesus, which said unto him, Before the cock crow, thou shalt deny me thrice. And he went out, and wept bitterly.
Luke 22:62
And Peter went out, and wept bitterly.