いい年をして[iitoshiwoshite] (in spite of) being old enough to know better
亥年[idoshi] year of the boar
一箇年[ikkanen] one year
一周年[isshuunen] one full year
一年以内に[ichineninaini] within a year

一年間[ichinenkan] (period of) one year
一年生[ichinensei] annual (plant)
一年草[ichinensou] annual (plant)
一年ぢゅう[ichinenjuu] all year round
一両年[ichiryounen] (a) year or two

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