Excessive; unduly large or inflated (beyond what is appropriate or realistic).
彼の功績を過大に評価してはいけない。
You shouldn't overestimate his achievements.
過大な期待は失望を招くことがある。
Excessive expectations can sometimes lead to disappointment.
予算を過大に見積もると後で問題になる。
Overestimating the budget causes problems later.