Strong’s Greek
G1414 — dunateo
The entry below is Strong’s own definition (1890, public domain), and every verse where the word occurs.
δυνατέω
dunateo — pronounced doo-nat-eh'-o
from 1415; to be efficient (figuratively):--be mighty. see GREEK for 1415
1 occurrence in the KJV.
2 Corinthians 13:3
Since ye seek a proof of Christ speaking in me, which to you-ward is not weak, but is mighty in you.