had been muffling

• past perfect progressive

  past perfect progressive

  Used to describe an action that was ongoing continuously in the past up until another past event interrupted it.

  of muffle.
  muffle

  verb (used with object)

  to wrap with something to deaden or prevent sound.

Related Words

• dampen
• deaden
• envelop
• hush
• mute
• muzzle
• soft pedal
• squelch
• stifle
• subdue
• tone down