Longman Dictionary of Contemporary English
The Collaborative International Dictionary
Impermissible \Im`per*mis"si*ble\, a. Not permissible.
Douglas Harper's Etymology Dictionary
a. Not permissible; not to be permitted or allowed.
adj. not permitted; "impermissible behavior" [ant: permissible]
Usage examples of "impermissible".
When, say, galley proofs were censored, the offending material was returned to the publisher with blue-penciled passages to be altered or deleted along with a standard form that simply indicated the paragraph or paragraphs of the ten-item Press Code that these impermissible passages violated.
We had just arrived at the delicate transition from astronomy, mathematics, and physics to the sciences of language and history, and the leader was a virtuoso in the art of setting traps for eager beginners like us and luring us on to the thin ice of impermissible abstractions and analogies.
Cuntish public-school drop-outs, dropped out for being too thick, having long hair or dirty boaters, unseaming new boys in multiple buggery, getting caught too many times with an impermissible number of hockey sticks up their bums.