From The Collaborative International Dictionary of English v.0.48 [gcide]:
dehydrated \dehydrated\ adj.
1. thoroughly dried out.
Syn: desiccated, dried-out.
[WordNet 1.5]
2. suffering from fluid deprivation; as, to become deydrated
from overexertion on a hot day.
[WordNet 1.5]
From WordNet (r) 3.0 (2006) [wn]:
dehydrated
adj 1: suffering from excessive loss of water from the body;
"fever resulted from becoming dehydrated"; "was
dehydrated after the marathon"
2: preserved by removing natural moisture; "dried beef"; "dried
fruit"; "dehydrated eggs"; "shredded and desiccated coconut
meat" [syn: dried, dehydrated, desiccated]