Surely you will not find this word, as it is, in your dictionary.
Do you remark this is a PS-t word? The base is כָּתַב, to write.
The best way to reach its meaning is taking a look at Index PS-t, where we find several items having נ as a prefix and ת as a suffix.
Only ptr PS-t1569 is the answer matching our word.
We thus get (female) written.