More on Lose Caste from Infoplease:

• Lose Caste - Lose Caste (To). (See Caste.) Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894 ...
• caste: meaning and definitions - caste: Definition and Pronunciation
• Caste - Caste (1 syl.), race. The Portuguese casta. In Sanskrit the word used for the same purpose is varna ...
• Dictionary of Phrase and Fable: L - Definitions, origins, and illustrative excerpts for words, phases, and literary allusions starting with "L"