The Greek noun gleukos (γλεῦκος) refers to new wine or sweet wine — freshly pressed grape juice or wine in early fermentation. It appears once in the New Testament (Acts 2:13), where mockers at Pentecost accused the disciples of being 'filled with new wine.' The accusation was simultaneously a misattribution and an unknowing metaphor.
The accusation of being drunk on gleukos at Pentecost is laced with irony. The mockers were wrong about the cause but not entirely wrong about the effect: the disciples were indeed filled — not with new wine but with the Holy Spirit, whose effects could look, from the outside, like intoxication. Paul draws on this same contrast in Ephesians 5:18: 'Do not get drunk on wine...instead, be filled with the Spirit.' The gleukos of Pentecost mockery becomes a metaphor for Spirit-filled abandon — the exhilarating fullness that comes from God.