Strong's G987 — βλασφημέω (verb)
blasphemeo (blas-fay-meh'-o) v.
1. to vilify
2. (specially) to speak irreverently
[from G989]
KJV: (speak) blaspheme(-er, -mously, -my), defame, rail on, revile, speak evil 
Root(s): G989 
Hebrew root: βλάσφημος
Occurrences: 35