skim milk

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Milk from which the cream has been removed.

from The Century Dictionary.

• noun Milk from which the cream has been skimmed; hence, figuratively, that which lacks substantial quality, as richness or strength; thinness; inferiority.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun North America Non-fat milk; milk that has had the cream removed.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun milk from which the cream has been skimmed