There are 16 words that end with 'niacs'.
| maniacs | ammoniacs |
| brainiacs | demoniacs |
| simoniacs | egomaniacs |
| insomniacs | monomaniacs |
| pyromaniacs | algolagniacs |
| dipsomaniacs | mythomaniacs |
| bibliomaniacs | megalomaniacs |
| kleptomaniacs | nymphomaniacs |
Note: These 16 words that end with 'niacs' are found from the USA & Canada version of the tournament Scrabble word list.