To insert or introduce between parts. To place (oneself) between others or things. To introduce or interject (a comment, for example) during discourse or a conversation. See Synonyms at introduce. To exert (influence or authority) in order to interfere or intervene: interpose one's veto. To come between things; assume an intervening position. To come between the parties in a dispute; intervene. To insert a remark, question, or argument.