Equivocation refers to the speech, from the appearance of which something is understood, while the purpose of speaker is something else.
It is well known among our jurists that the cases in which lie is prescribed for an exigency, equivocation should be applied, and as far as equivocation is possible, explicit lie is not advisable.
It is inferred from some phrases of Sunnite scholars that the same is popular among them.
And equivocation is defined to be when a man says something with a meaning in accordance with the reality, but the speech is so that listener understands something else, and this is the purpose of speaker that while willing a correct concept, the listener understands something else. For instance, one was asked, who the substitute of Prophet S.A is. He said, One whose daughter was in his house. The listener supposed that he meant the one whose daughter was in Prophet's S.A. house, but he meant one who Prophet's daughter was in his house.