马大哈mǎdàhā 1.粗心大意{heedless; unmindful}: 保管文件,可不能～。{One must not be careless when taking care of documents.} 2.指粗心大意的人{scatterbrain; careless and forgetful person}: 他是个～,做事总是丢三落四的。{He is so forgetful that he does nothing without leaving some loose ends.}