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

正閏[seijun] normal and leap (years)
閏月[uruuzuki] intercalary month
閏年[uruudoshi] leap year

閏秒[uruubyou] leap second
閏日[uruubi] leap day