impact impact /ˈɪmpækt/

noun

1. () The striking of one body against another  ( impact )
   the striking of one body against another
     The car crash had a devastating impact on their lives.
   The car crash had a devastating impact on their lives.
   
2. () A forceful consequence; a strong effect  ( wallop [Informal] , impact )
   a forceful consequence; a strong effect
    The book had an important impact on my thinking
   the book had an important impact on my thinking
    The book packs a wallop
   the book packs a wallop
   
3. () Influencing strongly  ( encroachment , impingement , impact )
   influencing strongly
    They resented the impingement of American values on European culture
   they resented the impingement of American values on European culture
   
4. The violent interaction of individuals or groups entering into combat  ( impact , shock )
   the violent interaction of individuals or groups entering into combat
    The armies met in the shock of battle
   the armies met in the shock of battle
   

verb

1. Have an effect upon  ( impact , touch on , bear upon , affect , bear on , touch )
   have an effect upon
    Will the new rules affect me?
   Will the new rules affect me?
   
2. Press or wedge together; pack together  ( impact )
   press or wedge together; pack together