WordNet (r) 3.0 (2006):

higher up
    adv 1: in or to a place that is higher [syn: above, higher
           up, in a higher place, to a higher place] [ant: at
           a lower place, below, beneath, to a lower place]

Moby Thesaurus II by Grady Ward, 1.0:

50 Moby Thesaurus words for "higher up":
   A per se, ace, boss, bureaucracy, champion, chief, commander, dean,
   directorate, fugleman, genius, head, hierarchy, higher echelons,
   higher-ups, laureate, leader, management, master, ministry,
   nonpareil, officialdom, paragon, prelacy, principal, prodigy,
   ruler, ruling class, ruling classes, senior, star, superior,
   superman, superstar, the Establishment, the administration,
   the authorities, the greatest, the ingroup, the interests,
   the most, the people upstairs, the power elite,
   the power structure, the top, them, they, top brass, top dog,
   virtuoso