Source : Webster's Revised Unabridged Dictionary (1913)

Impinge \Im*pinge"\, v. t. [imp. & p. p. {Impinged}; p. pr. &
   vb. n. {Impinging}.] [L. impingere; pref. im- in + pangere to
   fix, strike; prob. akin to pacisci to agree, contract. See
   {Pact}, and cf. {Impact}.]
   To fall or dash against; to touch upon; to strike; to hit; to
   ciash with; -- with on or upon.

         The cause of reflection is not the impinging of light
         on the solid or impervious parts of bodies. --Sir I.
                                                  Newton.

         But, in the present order of things, not to be employed
         without impinging on God's justice.      --Bp.
                                                  Warburton.

Source : WordNet®

impinging
     n : the physical coming together of two or more things; "contact
         with the pier scraped paint from the hull" [syn: {contact},
          {striking}]