Strong's G2001 — ἐπισχύω (verb)
epischuo (ep-is-khoo'-o) v.
1. to avail further
2. (figuratively) insist stoutly
[from G1909 and G2480]
KJV: be the more fierce 
Root(s): G1909, G2480 
Hebrew root: ἰσχύω
Occurrences: 1