interjection
alack
uh-LAK/əˈlæk/
An old-fashioned cry of sorrow or regret.
“Alack!” cries the actor, throwing up his hands over the broken jug.

Etymology
On Skeat’s account, this joins ah to lack in its older sense of loss, failure, or shame. Originally an expression of dissatisfaction, alack later became a cry of regret or unpleasant surprise.
In context
But alack! it's when he gets there his trouble will be, when none can warn him. Look how the waves are lashing the cliff
More examples
- Alack, we have arrived too late.
- The poem ends with a sorrowful alack.
- Alack, all their careful plans came to nothing.
Similar words
- alas
- Is a more familiar literary expression of sorrow or regret.
- unfortunately
- States regret directly without the old-fashioned exclamation.