Yes, flint is a Scrabble word!

Adjective

1. Showing unfeeling resistance to tender feelings

Noun

1. A hard kind of stone; a form of silica more opaque than chalcedony

2. A river in western Georgia that flows generally south to join the Chattahoochee River at the Florida border where they form the Apalachicola River

3. A city in southeast central Michigan near Detroit; automobile manufacturing