THESAURUS
on end
ad infinitum, again and again, at a stretch, at attention, bolt upright, ceaselessly, connectedly, constantly, continually, continuously, cumulatively, cyclically, endlessly, endways, endwise, erectly, incessantly, interminably, monotonously, on a stretch, on and on, perennially, repetitively, right
on end, round the clock, together, unbrokenly, unceasingly, unintermittently, uninterruptedly, unrelievedly, up, up
on end, upright, uprightly, upstandingly, without a break, without cease, without stopping
ROGET THESAURUS
on end
Verticality
N
verticality, erectness, perpendicularity, right angle, normal, azimuth circle, wall, precipice, cliff, elevation, erection, square, plumb line, plummet, vertical, upright, erect, perpendicular, plumb, normal, straight, bolt, upright, rampant, standing up, rectangular, orthogonal, vertically, up,
on end, up
on end, right
on end, a plomb, endwise, one one's legs, at right angles.