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

に過ぎない[nisuginai] no more than
マルコフ過程[marukofukatei] Markov process
為過ぎる[shisugiru] to overdo
一過[ikka] passing away
一過性[ikkasei] transient (pain or fever)

過ぎ[sugi] past
過ぎる[sugiru] to pass through
過ぎ去った可能性[sugisattakanousei] might-have-been
過去る[sugisaru] to pass
過す[sugosu] to pass (time)