What's the adjective for illegal? Here's the word you're looking for.
Included below are past participle and present participle forms for the
verbs illegalize and illegalise which may be used as adjectives within certain contexts.
“Coulson had resigned as the paper's editor following the conviction of a reporter in relation to illegal phone hacking, although stating that he knew nothing about it.”
“He was penalized by the umpire for an illegal tackle.”
“As an illegal resident, you can easily be exploited by a variety of ruthless persons, not the least of whom might be your landlord.”