v. t. [ imp. & p. p. Overrated; p. pr. & vb. n. Overrating. ] To rate or value too highly; to overestimate. [ 1913 Webster ]
n. An excessive rate. [ R. ] Massinger. [ 1913 Webster ]
n. a calculation that results in an estimate that is too high. Syn. -- overestimate, overestimation, overreckoning. [ WordNet 1.5 ]