Source : Webster's Revised Unabridged Dictionary (1913)

Overstep \O`ver*step"\, v. t. [imp. & p. p. {Overstepped}; p.
   pr. & vb. n. {Overstepping}.] [AS. ofersteppan.]
   To step over or beyond; to transgress. --Shak.

Source : WordNet®

overstep
     v 1: pass beyond (limits or boundaries) [syn: {transgress}, {trespass}]
     2: go beyond; "She exceeded our expectations"; "She topped her
        performance of last year" [syn: {exceed}, {transcend}, {pass},
         {go past}, {top}]
     [also: {overstepping}, {overstepped}]