Source : Webster's Revised Unabridged Dictionary (1913)

Striking \Strik"ing\, a.
   Affecting with strong emotions; surprising; forcible;
   impressive; very noticeable; as, a striking representation or
   image; a striking resemblance. ``A striking fact.'' --De
   Quincey. -- {Strik"ing*ly}, adv. -- {Strik"ing*ness}, n.

Source : WordNet®

strikingness
     n 1: the state of being salient [syn: {salience}, {saliency}]
     2: the quality of standing out strongly and distinctly [syn: {boldness}]