to injure or burn (something or somebody) with hot liquid or steam
to bring (a liquid, esp milk) almost to boiling point
to subject (something) to brief immersion in boiling water
archaic to rinse (something) in boiling water
like a scalded cat
very quickly
[Middle English scalden via early French escalder from late Latin excaldare to wash in warm water, from ex-1 + Latin calidus hot, warm]