unaccountably

Not able to be explained logically. Without being accountable, or reasonable.

Japanese Meaning

理屈で説明できない / 説明がつかない / 理由が判明しない

She smiled unaccountably during the tense interview, which only made the reporters more curious.

彼女は緊迫したインタビューの最中に不可解にも微笑み、それが記者たちの好奇心を一層かき立てた。

Sense（1）

Not able to be explained logically. Without being accountable, or reasonable.

After all that hard work, he unaccountably failed to take out the patent.

more unaccountably

（ comparative ）

most unaccountably

（ superlative ）