Strong’s Greek
G5570 — pseudapostolos
The entry below is Strong’s own definition (1890, public domain), and every verse where the word occurs.
ψευδαπόστολος
pseudapostolos — pronounced psyoo-dap-os'-tol-os
from 5571 and 652; a spurious apostle, i.e. pretended pracher:--false teacher. see GREEK for 5571 see GREEK for 652
1 occurrence in the KJV.
2 Corinthians 11:13
For such are false apostles, deceitful workers, transforming themselves into the apostles of Christ.