to the gills
Completely, utterly, or thoroughly. I was doped to the gills for about two weeks after my surgery. I'm off the painkillers now, but I still feel pretty out of it. I've got so many meetings and deadlines these days that my schedule is packed to the gills! We left the all-you-can-eat buffet full to the gills.
to the ˈgills
(informal) completely full: I was stuffed to the gills with chocolate cake. Gills are the openings on the side of a fish’s head that it breathes through.
to the gills
Informal As full as possible; completely.