impressive vs ineffectual

impressive

adj
  • Making, or tending to make, a positive impression; having power to impress 

  • Appealing. 

  • Capable of being impressed. 

ineffectual

adj
  • Weak, indecisive; lacking forcefulness. 

  • Unable or insufficient to produce effect. 

  • Worthless; ineffective. 

How often have the words impressive and ineffectual occurred in a corpus of books? (source: Google Ngram Viewer )