うらづける
to substantiate
裏付けることが大切です。
It is important to substantiate.
Try making sentences with this verb in different tenses. Active usage builds stronger recall than passive review. N2 vocabulary — this word appears in formal writing and news articles.
From the JLP Quiz question bank — the word in the form it is actually tested in.
研究者は自らの（ ）を裏付けるデータを積み重ね、論文にまとめた。
Answer: 仮説
