Is it farther or further?
1560s, with -some (1) + Middle English gruen "feel horror, shudder" (c.1300); not recorded in Old English or Norse, possibly from Middle Dutch gruwen or Middle Low German gruwen "shudder with fear" (cf. German grausam "cruel"), or from a Scandinavian source (cf. Danish grusom "cruel," grue "to dread," though others hold that these are Low German loan-words). One of the many Scottish words popularized in England by Scott's novels.