There are 14 words that start with 'false'.
false | falser | falsely |
falsest | falsetto | falseface |
falsehood | falseness | falsettos |
falsework | falsefaces | falsehoods |
falseworks | falsenesses | |
Note: These 14 words that start with 'false' are found from the USA & Canada version of the tournament Scrabble word list.