Unbook rhymes with:
book, create-a-book, rebook, book, brook, brooke, chinook, chook, cook, cooke, create-a-book, crook, crooke, decook, flook, forsook, gobbledygook, gook, hook, hooke, kirkuk, look, mccook, mistook, mook, nook, overcook, overtook, precook, rebook, retook, rook, rooke, schnook, schook, shook, snook, stroock, took, tooke, undercook, undertook, unhook, vanhook, zook
Unbook sounds like:
umbach, umbaugh, unambiguous, univisa, unpack