Synonyms of durably

1 Syllable
hard, fast, tight
2 Syllables
stably, stiffly, strongly, tightly, soundly, solid, firmly
3 Syllables
steadily, rigidly, thoroughly, forever, solidly, fixedly
4 Syllables
enduringly, immortally, inflexibly, motionlessly, unflinchingly, unshakeably, securely, substantially