thirst 
(thûrst)
(thûrst)n.
1.
a. A sensation of dryness in the mouth and throat related to a need or desire to drink.
b. The desire to drink.
2. An insistent desire; a craving: a thirst for knowledge.
intr.v. thirst·ed, thirst·ing, thirsts
1. To feel a need to drink.
2. To have a strong craving; yearn.
[Middle English, from Old English thurst; see ters- in the Appendix of Indo-European roots.]
thirster n.