What term refers to the measures that are not legally permissible for an officer to take?

The term that refers to the measures that are not legally permissible for an officer to take is "unlawful measures." This phrase clearly indicates that the actions in question violate legal statutes or regulations governing law enforcement conduct. Officers are expected to adhere to the law while performing their duties, and any actions deemed unlawful undermine the integrity of the law enforcement profession and can lead to serious legal repercussions for both the officer and the department.

The other terms, while suggesting negativity around the officer's actions, do not specifically convey the legal implications in the same way that "unlawful measures" does. "Excessive measures" often refers to actions that go beyond what is necessary but may not necessarily be illegal. "Unjustifiable measures" implies that an action cannot be justified ethically or morally, but again, it does not necessarily denote a breach of law. Similarly, "improper measures" suggests a lack of appropriateness without directly linking it to legality. Therefore, "unlawful measures" is the most precise term for actions that are explicitly forbidden by law.