There are 12 15-letter words that start with 'ir'.
| irasciblenesses | irrationalistic |
| irrationalities | irreconcilables |
| irreformability | irrefragability |
| irreparableness | irrepealability |
| irresistibility | irreversibility |
| irrevocableness | irritablenesses |
Note: These 12 15-letter words that start with 'ir' are found from the USA & Canada version of the tournament Scrabble word list.
Also see words start with irr, iro, iri, ira, ire, irk.
3-letter words start with 'ir' (2)