The Collaborative International Dictionary of English v.0.48:

Approximate \Ap*prox"i*mate\, v. t. [imp. & p. p.
   Approximated; p. pr. & vb. n. Approximating.]
   1. To carry or advance near; to cause to approach.
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            To approximate the inequality of riches to the level
            of nature.                            --Burke.
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   2. To come near to; to approach.
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            The telescope approximates perfection. --J. Morse.
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The Collaborative International Dictionary of English v.0.48:

Approximate \Ap*prox"i*mate\, v. i.
   To draw; to approach.
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The Collaborative International Dictionary of English v.0.48:

Approximate \Ap*prox"i*mate\, a. [L. approximatus, p. p. of
   approximare to approach; ad + proximare to come near. See
   Proximate.]
   1. Approaching; proximate; nearly resembling.
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   2. Near correctness; nearly exact; not perfectly accurate;
      as, approximate results or values.
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   Approximate quantities (Math.), those which are nearly, but
      not, equal.
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WordNet (r) 3.0 (2006):

approximate
    adj 1: not quite exact or correct; "the approximate time was 10
           o'clock"; "a rough guess"; "a ballpark estimate" [syn:
           approximate, approximative, rough]
    2: very close in resemblance; "sketched in an approximate
       likeness"; "a near likeness" [syn: approximate, near]
    3: located close together; "with heads close together";
       "approximate leaves grow together but are not united" [syn:
       approximate, close together(p)]
    v 1: be close or similar; "Her results approximate my own" [syn:
         approximate, come close]
    2: judge tentatively or form an estimate of (quantities or
       time); "I estimate this chicken to weigh three pounds" [syn:
       estimate, gauge, approximate, guess, judge]