Etymology Shortening of plusquamperfect, from Latin plusquamperfectum (“more than perfect”), from plus (“more”) + quam (“than”) + perfectum, neuter singular of perfectus (“achieved; finished; perfected”).
1
More than perfect, utterly perfect, ideal.
2
Grammar, Human sciences, Linguistics, Sciences Pertaining to action completed before another action or event in the past, past perfect.
3
Graph theory, Mathematics, Sciences Being or relating to a certain type of graph that complies with a theorem ("pluperfect graph theorem") discovered by D. R. Fulkerson in 1970, satisfying even more constraints than a perfect graph.
Informal Used as an intensifier in various interjections.
What in the pluperfect hell is going on here?!
The drought has raised pluperfect heck with fishing more ways than one.1952, North Carolina Wildlife Resources Commission, Wildlife in North Carolina - Volumes 16-19:
Etymology Shortening of plusquamperfect, from Latin plusquamperfectum (“more than perfect”), from plus (“more”) + quam (“than”) + perfectum, neuter singular of perfectus (“achieved; finished; perfected”).