Definition of "impactful"

We might suppose that some of the most impactful heroines of current films would combine these two functions: that of the good-bad girl ...

1950, Movies: A Psychological Study‎, Digitized edition, Free Press, published 2008, page 22

It is strongly recommended that in the future such investigations not be reported in the literature unless they are designed to test the effects of some hopefully impactful treatment variation.

1969, W. James Popham, “Curriculum Materials”, in Review of Educational Research, volume 39, number 3, page 321

Everyone knows that vividly presented information is impactful and persuasive.

1982, S. E. Taylor, S. C. Thompson, “Stalking the Elusive 'Vividness' Effect”, in Psychological Bulletin, volume 89, number 2, page 155

A dominant finding in psychology and consumer behavior has been that negative information is more impactful than positive information.

2001, A. Mukherjee, W. D. Hoyer, “The Effect of Novel Attributes on Product Evaluation”, in The Journal of Consumer Research, volume 28, number 3, page 463

“The evening will help to raise money to create a place where children can have fun and enjoy playing for years to come; a fitting legacy of a short-lived but impactful life."

2013 March 22, “Pals organise night out to remember Florence”, in West Sussex Gazette