D defs.my
Entry 2 senses Webster, 1913

Deafen

/dĕf'-ən/ · Deaf·en · IPA /ˈdɛfən/
01 v. t. To make deaf; to deprive of the power of hearing; to render incapable of perceiving sounds distinctly.
imp. & p. p. Deafened; p. pr. & vb. n. Deafening
  1. 1.
    To make deaf; to deprive of the power of hearing; to render incapable of perceiving sounds distinctly.
    Deafened and stunned with their promiscuous cries.” Addison.
  2. 2.
    To render impervious to sound, as a partition or floor, by filling the space within with mortar, by lining with paper, etc.(Arch.)