1im·pact 
/ˈɪmˌpækt/ noun
plural im·pacts /ˈɪmˌpækt/ noun 1 : the act or force of one thing hitting another [count] ▪ No one could have survived such an impact. [noncount] ▪ The bomb exploded on/upon impact (with the ground). [=when it hit the ground] 2 [count] : a powerful or major influence or effect
▪ These warnings have been heard so often that they have lost their impact. ▪ The book had a huge impact when it first came out. ▪ We need to be concerned about the environmental impacts of all this construction. ▪ She expects to make an immediate impact at work. — often + on ▪ The stress of her job is having a negative impact on her health. [=is harming her health] ▪ We hope that these programs will have a positive impact on the community. [=will help the community]
▪ These warnings have been heard so often that they have lost their impact. ▪ The book had a huge impact when it first came out. ▪ We need to be concerned about the environmental impacts of all this construction. ▪ She expects to make an immediate impact at work. — often + on ▪ The stress of her job is having a negative impact on her health. [=is harming her health] ▪ We hope that these programs will have a positive impact on the community. [=will help the community]
