| impermissibility | (n) inadmissibility as a consequence of not being permitted, Ant. permissibility |
| impermissible | (adj) not permitted, Ant. permissible, Example: impermissible behavior |
| impermissible | (adj) not allowable |
| impermissibly | (adv) not permissibly, Ant. permissibly, Example: the radon level in the basement was impermissibly high |
| Impermissible | a. Not permissible. [ 1913 Webster ] |