over-estimation

verb (used with object), o·ver·es·ti·mat·ed, o·ver·es·ti·mat·ing.

1. to estimate at too high a value, amount, rate, or the like: Don’t overestimate the car’s trade-in value.
2. to hold in too great esteem or to expect too much from: Don’t overestimate him—he’s no smarter than you are.

noun

3. an estimate that is too high.

verb (ˌəʊvərˈɛstɪˌmeɪt)

1. (tr) to value or estimate too highly

noun (ˌəʊvərˈɛstɪmɪt)

2. an estimate that is too high

n.1793, noun of action from over-estimate (v.).