健忘[kenbou] forgetfulness
健忘症[kenboushou] amnesia
度忘[dowasure] lapse of memory
胴忘[douwasure] lapse of memory
年忘れ[toshiwasure] year-end drinking party

備忘[bibou] reminder
備忘録[bibouroku] notebook
忘る[wasuru] to lose something
忘れっぽい[wasureppoi] forgetful
忘れる[wasureru] to forget