'Bitter' in the Bible

Then David gave way to bitter grief, and so did all the men who were with him:

Then crying out to Joab, Abner said, Are fighting and destruction to go on for ever? do you not see that the end will only be bitter? how long will it be before you send the people back and make them give up attacking their countrymen?

Hushai said further, You have knowledge of your father and his men, that they are men of war, and that their feelings are bitter, like those of a bear in the field whose young ones have been taken from her: and your father is a man of war, and will not take his night's rest with the people;

And the salvation of that day was changed to sorrow for all the people: for it was said to the people, The king is in bitter grief for his son.