逝去 is read as せいきょ (seikyo) and means death.
せいきょ
seikyo
てっきょ
removal
かていほうかこ
subjunctive past
いんせんいんめんしょうきょ
hidden line and surface removal
いんせんしょうきょ
hidden-line elimination
さっきょ
いんめんしょうきょ
hidden surface removal
かこ
one's past (that one would prefer remained secret)
しきょ
death
しょうきょ
elimination (of variables)
じょきょ
たいきょ
recession
ふていかこ
aorist tense (in Greek)