'Bitterness' in the Bible

O daughter of my people, gird yourself [with] sackcloth, and roll about in the ashes in mourning, a mourning ceremony [as for] an only child. Make for yourself wailing of bitterness, for suddenly the destroyer will come upon us.

Therefore thus says the Lord of hosts in regard to the prophets,‘Behold, I am going to feed them [the bitterness of] wormwoodAnd make them drink the poisonous water [of gall],For from the [counterfeit] prophets of JerusalemProfaneness and ungodliness have spread into all the land.’”

Thus says Yahweh, "A voice [is] heard in Ramah, lamentation, [the] weeping of bitterness. Rachel [is] weeping for her children; she refuses to be comforted because of her children, for they are no [more]."