Here are some synonyms for "lament":
* Mourn
* Grieve
* Weep
* Cry
* Complain
* Deplore
Here are some examples of how "lament" can be used in a sentence:
* "The old woman lamented the loss of her beloved husband."
* "The poet wrote a lament for the fallen soldiers."
* "He lamented the fact that he had missed his chance to go to college."
Note: "Lament" can also be used as a noun, referring to an expression of grief or sorrow. For example, "The lament of the bereaved family was heart-wrenching."