From Longman Dictionary of Contemporary Englishstowawaystow‧a‧way /ˈstəʊəweɪ $ ˈstoʊ-/ noun [countable] HIDE/MAKE IT HARD TO FIND OR SEEsomeone who hides on a vehicle in order to travel secretly or to avoid paying
Examples from the Corpus
stowaway• An exception to this solemnity comes when Mr Raban breaks his own rule and allows stowaways on board. 