Third person singular present tense; removes water from something or causes someone to lose fluids and become dehydrated.
From dehydrate + -s (third person singular). The verb has both transitive (to remove water from) and intransitive (to lose water) meanings.
Surprisingly, eating salty snacks dehydrates you because salt actually pulls water out of your cells and into your bloodstream, which is why you get thirsty after eating chips!
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