安全期[anzenki] safe period
暗黒期[ankokuki] eclipse period
一期[ichigo] one's life time
一期[ikki] one term
一期一会[ichigoichie] once-in-a-lifetime encounter (hence should be cherished as such)

一周期[isshuuki] period (in astronomy)
一定期間[itteikikan] fixed interval
延期[enki] postponement
延期になる[enkininaru] to be postponed
沖積期[chuusekiki] alluvial period

御手盛り[otemori] making arbitrary decisions which benefit oneself
いたずら盛り[itazurazakari] mischievous age
人生の真っ盛り[isshounomassakari] the noontide of life
一盛り[hitosakari] temporary prosperity
一盛り[hitomori] pile

栄枯盛衰[eikoseisui] ups and downs of life
旺盛[ousei] full of vim and vigor
花盛り[hanazakari] flowers in full bloom
勤め盛り[tsutomezakari] the prime of one's career
最盛期[saiseiki] golden age