Definitions

1. interjection

an expression of sorrow, dismay, or disappointment

“Alack, I forgot my phone at home.”

2. noun

an expression of sorrow or regret

“The alack that followed the news of the accident was palpable.”

3. verb

to express sorrow or regret

“She alacked the situation, feeling sorry for the person involved.”

4. adverb

in a sorrowful or regretful manner

“He alacked the news, feeling sad and disappointed.”