The Greek noun apousia means absence, or the state of being away. It is the antonym of parousia (presence/coming) and appears only once in the New Testament. It comes from apo- (away) and eimi (to be).
Apousia appears in Philippians 2:12, where Paul writes: 'Therefore, my dear friends, as you have always obeyed — not only in my presence, but now much more in my absence — continue to work out your salvation with fear and trembling.' The theological point is profound: authentic Christian obedience is not performance for an overseer but a response to the indwelling Holy Spirit. The contrast with parousia (presence) highlights the maturity Paul calls for — faith that is equally obedient whether seen or unseen. God's omnipresence means no Christian is ever truly unobserved.