Viper rhymes with:
dekuyper, diaper, hyper, kiper, kuyper, piper, pyper, sniper, striper, vanriper, wiper
Viper sounds like:
vapor, vaporware, vara, vari, varo, vary, vavra, veer, veira, ver, vera, vere, verhey, vero, veroa, verri, verrier, verry, verwey, very, viar, vieira, viera, vierra, viewer, vieyra, viray, vivier, vivra, voir, vora, vore, vorhauer, voyer, voyeur