Strong’s Greek
G5569 — pseudadelphos
The entry below is Strong’s own definition (1890, public domain), and every verse where the word occurs.
ψευδάδελφος
pseudadelphos — pronounced psyoo-dad'-el-fos
from 5571 and 80; a spurious brother, i.e. pretended associate:--false brethren. see GREEK for 5571 see GREEK for 80
1 occurrence in the KJV.
Galatians 2:4
And that because of false brethren unawares brought in, who came in privily to spy out our liberty which we have in Christ Jesus, that they might bring us into bondage: