particle, conjunction
Concessive conjunction used after a clause to mean 'although' or 'despite the fact that'. Often implies that the result is contrary to what might be expected. Common in both spoken and written Japanese.
彼は若いものの、とてもしっかりしている。
Although he is young, he is very reliable.
努力したものの、結果は思わしくなかった。
Even though I tried hard, the results were not satisfactory.