There are 18 words that end with 'nna'.
anna | canna | donna |
henna | manna | pinna |
penna | senna | sunna |
duenna | goanna | sienna |
antenna | hosanna | madonna |
savanna | bandanna | belladonna |
Note: These 18 words that end with 'nna' are found from the USA & Canada version of the tournament Scrabble word list.