The Collaborative International Dictionary of English v.0.48:
Borrower \Bor"row*er\, n. One who borrows. [1913 Webster] Neither a borrower nor a lender be. --Shak. [1913 Webster]WordNet (r) 3.0 (2006):
borrower n 1: someone who receives something on the promise to return it or its equivalent [ant: lender, loaner]