According to Merriam-Webster, "quirky" describes something that is strange or different from the ordinary in a peculiar way that causes curiosity or suspicion. An unusual habit or occurrence may also be called "quirky."
"Quirky" describes objects, people and even places. Quirky weather describes weather that is very different from what is expected, such as very hot days in midwinter. An individual who dresses or behaves in a manner that is bizarre or peculiar is described as quirky. Even a machine that does not operate as expected has its quirks or is quirky. Some synonyms for quirky are offbeat, peculiar, outlandish, curious and bizarre.