adj. difficult to break and therefore able to withstand rough usage
adj. not able to be broken in
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
adj. impossible to break especially under ordinary usage
Word Usage
"My last two pairs of lenses, both Varilux Comfort, one polarized, one clear, both in unbreakable polycarbonate, with non-reflective coatings, cost US$860 from a small private optician in New England."