This is the 6862nd most frequent Dutch word.
aantoonbaar
Demonstrable.
Here, 'aantoonbaar' is used to indicate that the error could be clearly identified and demonstrated.
De fout in zijn berekening was aantoonbaar en duidelijk voor iedereen.
The error in his calculation was demonstrable and clear to everyone.
In this sentence, 'aantoonbaar' refers to the success that can be evidenced or proven.
Zijn aantoonbaar succes laat zien hoe hard hij heeft gewerkt.
His demonstrable success shows how hard he has worked.
Here, 'aantoonbaar' is used to convey the notion that it is subject to being proven false.