"a steep, rugged rock; rough, broken, projecting rock, especially a sea-cliff," early 14c. (as a place-name element from c. 1200), probably from a Celtic source akin to Old Irish crec "rock," and carrac "cliff," Welsh craig "rock, stone," Manx creg, Breton krag. A cragsman (1815) is "one dexterous in climbing cliffs overhanging the sea to get the eggs of sea-birds."
adjective suffix, "full of or characterized by," from Old English -ig, from Proto-Germanic *-iga- (source also of Dutch, Danish, German -ig, Gothic -egs), from PIE -(i)ko-, adjectival suffix, cognate with elements in Greek -ikos, Latin -icus (see -ic). Originally added to nouns in Old English; used from 13c. with verbs, and by 15c. even with other adjectives (for example crispy).
<a href="https://www.etymonline.com/word/craggy">Etymology of craggy by etymonline</a>
Harper, D. (n.d.). Etymology of craggy. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/craggy