‘By my faith!’ (as an asseveration); = mafey, int. Cf. perfay, int.

In asseverative phrases. In quasi-oaths. by, upon my (etc.) fay: = faith, n. int.phrases 1a(a)(ii). Also in French form, (par) (ma) fay.

by one's faith: on one's word of honour, truly; assuredly. Chiefly used parenthetically as an oath or to emphasize the truth of a statement, esp. in b…

‘By my faith!’ (as an asseveration); = par ma fay, int.

Originally: ‘by my faith!’ (as an asseveration). Later: ‘heavens!’, ‘goodness!’ Cf. mafey, int.

Elaborated as by the faith of one's body (also love). Now rare and archaic.

A religious system; the Christian, Jewish, Muslim, or Pagan religion. by my law: by my faith; also to swear one's law. Cf. lay, n.3

by my vusse, used as an asseveration.

Used, esp. by 17th and 18th century dramatists, as a trivial oath amounting to a simple asseveration: In faith, by my faith.

In faith.

A euphemistic substitute for faith, int. or i'faith at faith, n. int.phrases 1a(b), used as a mild oath.

Chiefly in phrase, my certie, as an ejaculation: By my faith, in good troth.