Strong’s Greek
G830 — authairetos
The entry below is Strong’s own definition (1890, public domain), and every verse where the word occurs.
αὐθαίρετος
authairetos — pronounced ow-thah'-ee-ret-os
from 846 and the same as 140; self-chosen, i.e. (by implication) voluntary:--of own accord, willing of self. see GREEK for 846 see GREEK for 140
2 occurrences in the KJV.
2 Corinthians 8:3
For to their power, I bear record, yea, and beyond their power they were willing of themselves;
2 Corinthians 8:17
For indeed he accepted the exhortation; but being more forward, of his own accord he went unto you.