impactful

From impact +‎ -ful.

• IPA^(key): /ˈɪmpæktfəl/, /ɪmˈpæktfəl/

impactful (comparative more impactful, superlative most impactful)

1. Having impact. [from c. 1940]
   • 1950, Movies: A Psychological Study‎, Digitized edition, Free Press, published 2008, page 22:

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

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

     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.

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

     Everyone knows that vividly presented information is impactful and persuasive.

   • 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:

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

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

     “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."

• Proscribed by some authorities, who recommend influential or effective instead.[1] Alternatively, one may rephrase to have an impact or have a strong impact. However, many usages can be found, particularly in business and education[1] as well as in journalism and academic writing.
• Usage is more common in the US.

• effectual, impactive, consequential, significant, eventful

• impactless

• impactfully
• impactfulness

• “impactful”, in OneLook Dictionary Search.
• impactful, having impact, impactive at Google Ngram Viewer