← BackshareGuessshelliest/ˈʃɛliɪst/adjectiveHaving the most shell-like qualities, such as being hard, brittle, or layered.The shelliest part of the cliff crumbled easily in my hand.This is the shelliest piece of shale I've ever seen.Among all the fossils, this one felt the shelliest.SynonymsbrittlecrustyhardAntonymssoftflexible