Entryphao (ἐντρυφάω) means to revel in or find sensual delight in something — to indulge luxuriously. It combines en (in) with tryphe (luxury, indulgence). The word appears only once in the New Testament — in 2 Peter 2:13 — describing false teachers who 'revel [entryphao] in their pleasures while they feast with you.' The same root (tryphe) is used in Luke 7:25 for those who live in luxury in royal palaces, and in Revelation 18:7,9 for Babylon's luxurious indulgence.
Entryphao in 2 Peter 2:13 is part of a devastating portrait of false teachers: they attend Christian fellowship meals while secretly reveling in their own sensual pleasures. The contrast with genuine Christian fellowship (agape feast) is sharp — they participate in the form of community while pursuing its opposite in substance. The word warns against the corruption that comes when spiritual community becomes a cover for personal indulgence. Paul's warning about 'enemies of the cross of God whose god is their belly' (Philippians 3:18-19) uses similar imagery.