adj. sorrowful; unfortunate
adv. sorrowfully; unfortunately
n. sorrow
v. to sorrow, feel sorrow; to make or become sorrowful
interj. apologies, pardon, sorry

But you have indulged my weakness for speech long enough. Krosis. Now I will answer your question.
Krosis = sorrow (“Apologies”)
(Paarthurnax, 000556D9)

Lingrah krosis saraan Strundu'ul, voth nid balaan klov praan nau.
Long sorrowfully (has) waited the Stormcrown, with no worthy head to rest on.
(Greybeards, 000C43AB)

Het nok Yngnavar Gaaf-Kodaav, wo drey Yah moro nau Frod do Krosis, nuz sinon siiv dinok ahrk dukaan.
Here lies Yngnavar Ghost-Bear, who did Seek glory on the Battlefield of Sorrows, but instead found death and dishonor.
(Word Wall for Yah, Aura Whisper)

Often used as an interjection to express misfortune or regret, not to be confused as exclusively meaning ‘apologies’.