There are 42 15-letter words that start with 'hyper'.
Note: These 42 15-letter words that start with 'hyper' are found from the USA & Canada version of the tournament Scrabble word list.
Also see words start with hyperp, hyperc, hyperm, hypers, hypere, hypert, hyperb, hypera, hyperi, hyperr, hypero, hyperv, hyperg, hyperl, hyperk, hyperf, hyperu, hyperh.
6-letter words start with 'hyper' (1)