This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
岴 combines 山 (mountain) with 丘 (hill), suggesting a steep or rugged hill. The exact historical development is uncertain.
A mountain 山 beside a hill 丘 suggests a steep, rugged slope. The shape itself hints at a difficult, precipitous terrain.
For ク, imagine a steep hill so rugged that climbers say 'coo' in awe: coo -> ク, as they gaze up at the daunting slope.