2. Rock Climbing and Mountaineering. Friable, crumbly, or loose rock, typically considered unsafe or unpleasant to climb. Cf. chossy adj.
1963 A. Greenbank Instr. Rock Climbing vi. 71 The first climb..up broken, vegetation-clad rocks simply used to lead the climber to one hard pitch, and then get him off by another section of ‘choss’.
1975 Sc. Mountaineering Club Jrnl. No. 166. 329 ‘If that's typical of the Taurus Mountains it seems a long way to go to climb a heap of choss’ he muttered.
2014 L. B. Crompton Adrenaline Crush ii. 16 My stomach plummets and I quickly examine the surrounding rock face for other signs of choss.
Rock Climbing and Mountaineering.
Of rock, a rock face, etc.: friable, crumbly, loose; consisting of such rock, esp. characterized as unsafe or unpleasant to climb.
1965 Climber Mar. 24/1 We start slithering down, facing outwards, on chossy slabs leading to the rows of cars looking from here like paints in a paintbox.
1984 Sc. Mountaineering Club Jrnl. No. 175. 62 Climb the jamming crack just left of an obvious chossy chimney.
1996 Climbing 1 Feb. 103/2 Beware of its heinous loose approach and wet, chossy rock.
2012 S. M. Green Rock Climbing Utah (new ed.) 488/2 The diverse layers of limestone, at first glance, appear chossy and devoid of good holds.