Strong's G471 — ἀντέπω (verb)
antepo (an-tep'-o) v.
1. (properly) to speak against
2. (concretely) to refute or deny
[from G473 and G2036]
KJV: gainsay, say against 
Root(s): G473, G2036 
Hebrew root: ἔπω
Occurrences: 2