Source : Webster's Revised Unabridged Dictionary (1913)

Fastidious \Fas*tid"i*ous\, a. [L. fastidiosus disdainful, fr.
   fastidium loathing, aversion, perh. fr. fastus arrogance (of
   uncertain origin) + taedium loathing. Cf. {Tedious}, {Fash}.]
   Difficult to please; delicate to a fault; suited with
   difficulty; squeamish; as, a fastidious mind or ear; a
   fastidious appetite.

         Proud youth ! fastidious of the lower world. --Young.

   Syn: Squeamish; critical; overnice; difficult; punctilious.
        

   Usage: {Fastidious}, {Squeamish}. We call a person fastidious
          when his taste or feelings are offended by trifling
          defects or errors; we call him squeamish when he is
          excessively nice or critical on minor points, and also
          when he is overscrupulous as to questions of duty.
          ``Whoever examines his own imperfections will cease to
          be fastidious; whoever restrains his caprice and
          scrupulosity will cease to be squeamish.'' --Crabb. --
          {Fas*tid"i*ous*ly}, adv. -- {Fas*tid"i*ous*ness}, n.

Source : WordNet®

fastidious
     adj 1: giving and careful attention to detail; hard to please;
            excessively concerned with cleanliness; "a fastidious
            and incisive intellect"; "fastidious about personal
            cleanliness" [ant: {unfastidious}]
     2: having complicated nutritional requirements; especially
        growing only in special artificial cultures; "fastidious
        microorganisms"; "certain highly specialized xerophytes
        are extremely exacting in their requirements" [syn: {exacting}]
        [ant: {unfastidious}]