unfortunately

adverb
un·for·tu·nate·ly
/ʌnˈfɔː.tjʊ.nət.li/

Happening through bad luck, or because of some unfortunate event.

Example

“He unfortunately placed his hand on a loose brick.”

Other meanings

Used (as a parenthetical word, often a sentence adverb) to express disappointment, compassion, sorrow, regret, or grief.
“The houses which burned down could have been saved. Unfortunately, the fire truck had broken down on the way.”

Example sentences

“Unfortunately, I can't help at the moment.”
Tatoeba · shekitten · CC0
“Unfortunately, it doesn't really seem to be true.”
Tatoeba · ddnktr · CC0
“Unfortunately, we're unable to accommodate your request.”
Tatoeba · hecko · CC0

Where this comes from

This definition is adapted from “unfortunately” on Wiktionary, by its contributors; example sentences are from Tatoeba, credited to their authors above, published under CC BY-SA 4.0. This page is published under the same licence.