In composition out has either its ordinary adverbial sense, as in outcast, outcome, outlook, etc., or a prepositional force, as in outdoors, or forms transitive verbs denoting a going beyond or surpassing of the object of the verb, in doing the act expressed by the word to which it is prefixed, as in outrun, outshine, outvenom, etc. In the last use especially out may be used with almost any noun or verb. [Century Dictionary]
在組合中， out 要麼具有其普通的副詞意義，如 outcast, outcome, outlook 等，要麼具有介詞的力量，如 outdoors，或者形成及物動詞，表示做實際動作時在該詞前綴所表達的對象上超越或超過，如 outrun, outshine, outvenom 等。在最後一種使用中，Out 幾乎可以與任何名詞或動詞一起使用。[世紀詞典]
