1.Lit. to desire something to drink. (Somewhat formal.) "I thirst for something cooling and refreshing." said the preacher. You could see that everyone there was thirsting for water, or even coffee, but there was no refreshment in sight.
2.Fig. to have a strong desire for something. (See also have a thirst for something.) In the old days, students were said to thirst for knowledge. The generals thirsted for new battles to be fought.