Strong's #5420: phrasso (pronounced fras'-so)
 apparently a strengthening form of the base of 5424; to fence or inclose, i.e. (specially), to block up (figuratively, to silence):--stop.
Thayer's Greek Lexicon:
 ́ 
 
  phrassō 
 
 1) to fence in, block up, stop up, close up
 2) to put to silence
 
  Part of Speech: verb
Relation: apparently a strengthening form of the base of G5424
 
Usage:
This word is used 2 times:
Romans 3:19: "that every mouth  may be stopped, and all the world"
Hebrews 11:33: "righteousness, obtained promises,  stopped the mouths of lions,"