Fetching details from the dictionary...

to lament; to grieve; to regret
to deplore
彼女は自分の運命を嘆いてばかりいる。
She does nothing but lament her fate.
この世の中の不公平さを嘆く声が多い。
There are many voices lamenting the unfairness of this world.
友人の死を嘆き悲しむ日々が続いた。
Days of grieving over my friend's death continued.