earplug UK /ˈɪəplʌɡ/US /ɪɚplʌɡ/noun 1verb 1forms 3 noun1 •A piece of protective gear meant to be inserted in the ear canal to protect the wearer's hearing from loud noises or the intrusion of water. verb1 •To fit with earplugs.In this same strain of mouse, earplugging from 17-22 days postpartum is effective in inducing susceptibility to audiogenic seizures... — 1975 formsearplugged · earplugging · earplugs