ἐπιμαρτυρέω
to bear witness to
ἐπιμαρτυρέω to attest further, i.e. corroborate
Derivation: from G1909 and G3140;
KJV Usage: testify. G1909 G3140
Thayer:
1) to bear witness to, establish by testimony

ἐπιμαρτυρέω
epimartureō
ep-ee-mar-too-reh'-o
From G1909 and G3140; to attest further, that is, corroborate
KJV Usage: testify.