ad.
1.
In eternal wise. See the adjective under 1, 3, 4, 5.
2.
Endlessly, interminably, perpetually, ceaselessly, continually, everlastingly, always, ever, aye, evermore, for everlasting, forever, for aye, forever and ever, world without end, time without end, to the end of time, till doomsday.