The Collaborative International Dictionary of English v.0.48:

High \High\, adv.
   In a high manner; in a high place; to a great altitude; to a
   great degree; largely; in a superior manner; eminently;
   powerfully. "And reasoned high." --Milton. "I can not reach
   so high." --Shak.
   [1913 Webster]

   Note: High is extensively used in the formation of compound
         words, most of which are of very obvious signification;
         as, high-aimed, high-arched, high-aspiring,
         high-bearing, high-boasting, high-browed, high-crested,
         high-crowned, high-designing, high-engendered,
         high-feeding, high-flaming, high-flavored, high-gazing,
         high-heaped, high-heeled, high-priced, high-reared,
         high-resolved, high-rigged, high-seated,
         high-shouldered, high-soaring, high-towering,
         high-voiced, and the like.
         [1913 Webster]

   High and low, everywhere; in all supposable places; as, I
      hunted high and low. [Colloq.]
      [1913 Webster]

WordNet (r) 3.0 (2006):

high and low
    adv 1: everywhere; "searched high and low"