幻を追う[maboroshiwoou] to pursue an illusion
幻影[genei] phantom
幻覚[genkaku] hallucination
幻覚剤[genkakuzai] hallucinogen
幻姿[genshi] apparition

幻視[genshi] visual hallucination
幻想[gensou] illusions
幻想劇[gensougeki] non-realistic drama
幻像[genzou] phantom

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