by 1973 (said to date to 1960s in DAS), Black English, from hairdo + rag (n.).
Slang definitions & phrases for do-rag
do-rag
modifier
: that famous do-rag militant, Sammy Davis
noun
A cloth or scarf worn over a processed hairdo or ''conk'': wears a ''do-rag'' on his new hairdo as he pours out hatred of whites/ Plaid work shirt, do-rag, pointy-toed shoes(1960s+ Black)