ETYM Old Eng. feith, fayth, fay, Old Fren. feid, feit, fei, French foi, from Latin fides.
1. Complete confidence in a person or plan etc; SYN. trust.
2. Loyalty or allegiance to a cause or a person.
In religion, trust and belief in God’s provision; the “assurance of things hoped for, the conviction of things not seen” (St Paul). It can also mean a particular religion or set of beliefs.
The idea of faithfulness, in the sense of commitment or steadfastness, can be applied to both human beings and God. Faith includes moral or liturgical obedience, although in Christianity the Protestant reformers made a sharp distinction between faith (belief in Jesus Christ as the only way to salvation) and works (practical actions), which they taught did not bring salvation. In Hinduism, faith is defined as dependence on God in devotion. In Buddhism, faith is one of the five cardinal virtues, and is an essential part of the search for enlightenment.

ETYM Old Eng. faute, Old Fren. fauté, fealté, feelé, feelteit, from Latin fidelitas, from fidelis faithful. Related to Feal, Fidelity.
1. Fidelity to one's lord; the feudal obligation by which the tenant or vassal was bound to be faithful to his lord; the special oath by which this obligation was assumed.
2. Fidelity; constancy; faithfulness, as of a friend to a friend, or of a wife to her husband.
Loyalty; duty, especially of vassal to feudal lord.
In feudalism, the loyalty and duties owed by a vassal to his lord. In the 9th century fealty obliged the vassal not to take part in any action that would endanger the lord or his property, but by the 11th century the specific duties of fealty were established and included financial obligations and military service. Following an oath of fealty, an act of allegiance and respect (homage) was made by the vassal; when a fief was granted by the lord, it was formalized in the process of investiture.

ETYM French piété; cf. Italian pietŕ; both from Latin pietas piety, from pius pious. Related to Pious, Pity.
Righteousness by virtue of being pious; SYN. piousness.

ETYM A variant of truth. Related to Truth.
1. Belief; faith; fidelity.
2. Truth; verity; veracity.
3. Betrothal.