Exhaustive describes work that covers everything — nothing left out, every possibility checked. "The police carried out an exhaustive search of the building" means they looked in every room, every cupboard, everywhere. It is a word for searches, studies, lists, tests, and reports: the kind of thing someone does carefully and completely. There is a common polite phrase, "this list is not exhaustive," which is a writer's way of saying "there are more examples than the ones I gave you." You see it a lot in official documents and rules. The tone is formal — it belongs to written English and careful speech, not to chatting with friends. One thing worth knowing: because it is so complete, exhaustive work usually takes a long time and a lot of effort, so the word often carries a faint feeling of "this was hard to do." But the meaning itself is about coverage, not about tiredness.