plenipotent
adjective
ple·nip·o·tent pli-ˈni-pə-tənt 
: plenipotentiary
Word History
Etymology
borrowed from Late Latin plēnipotent-, plēnipotens, from Latin plēnus "full" + -i- -i- + potent-, potens "powerful" — more at full entry 1, potent entry 1
First Known Use
1639, in the meaning defined above