Always beware that in English, the use of a past participle as an adjective is ambiguous between transitive and intransitive verbs (and perhaps between active and passive voice). isRecovered might mean that the object has been recovered by something else, or it might mean that the object has recovered. If your object represents a patient at a hospital, does "isRecovered" mean that the patient is fit and well, or that someone has fetched the patient back from the X-ray department? wasRecovered might therefore be better for the latter.
Like this but with attributes/adjectives https://segment.com/academy/collecting-data/naming-conventions-for-clean-data/
If the property/method is a boolean, use isVal() or hasVal().