Source : Webster's Revised Unabridged Dictionary (1913)

Approximative \Ap*prox"i*ma*tive\, a. [Cf. F. approximatif.]
   Approaching; approximate. -- {Ap*prox"i*ma*tive*ly}, adv. --
   {Ap*prox"i*ma*tive*ness}, n.

Source : WordNet®

approximative
     adj : not quite exact or correct; "the approximate time was 10
           o'clock"; "a rough guess"; "a ballpark estimate" [syn:
           {approximate}, {rough}]