Regrettable (adjective)

1. Worthy of regret; unfortunate; sad.
2. Provoking regret; causing remorse.

Origin:

Mid 16th century (in the sense "worthy of regret"): from french regrettable or latin regrettabilis, from the verb regreter "to regret".

Examples:

1. It is regrettable that he couldn't make it to the party.
2. The loss of the game was a regrettable outcome.
3. The accident was a regrettable event that could have been avoided.
4. The decision to cancel the project was regrettable but necessary.
5. The loss of the historic building was a regrettable consequence of the new construction.