clamber

From Middle English clambren, clameren, clemeren (“to climb, clamber; to crawl, creep”), then either:

possibly from clam, clamb, clemb, past tense of climben (“to climb, get over; to ascend, rise”), and influenced by Old English clæmman (“to press”); or

from Old English *clambrian, from Proto-Germanic *klambrōną or *klambizōną.

The English word is cognate with Low German klemmern, klempern (“to climb”), Scots clammer (“to clamber”); and compare also Danish klamre (“to cling”), Icelandic klambra, klembra (“to pinch closely together; clamp”), Swedish klamra (“to cling”).

The noun is derived from the verb.