古往今来[kooukonrai] in all ages
古今[kokon] ancient and modern times
古今東西[kokontouzai] all times and places
古今無類[kokonmurui] best ever

今か今か[imakaimaka] eagerly waiting
今が今[imagaima] just now
今が今まで[imagaimamade] till just now
今しがた[imashigata] moment ago

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