fid-, fidel-

(Latin: believe, belief; trust, faith, true)

fideicide (s) (noun), fideicides (pl)
A breaker of one’s word or trust; a destroyer of trust.
fideism (s) (noun) (no plural form)
A reliance, in a search for religious truth, on faith alone.
Fidelitas, veritas, integritas. (Latin motto)
Translation: "Fidelity, truth, integrity."

Motto of Salmon P. Chase College of Law of Northtern Kentucky University, Covington, Kentucky, USA.

fidelity (s) (noun), fidelities (pl)
1. The quality of being trustworthy, loyalty, unswerving allegiance to a person, party, bond, etc.
2. Strict conformity to truth or fact.
3. Faithfulness to a sexual partner; especially, a husband or wife.
4. The degree to which a sound or picture reproduced or transmitted by any device resembles the original; especially, in high fidelity.

A person’s loyalty is determined by observing what one stands for, falls for, and lies for.

—John Rayoa
Fides et justitia. (Latin motto)
Translation: "Faith and justice."
Fides lumen praebeat. (Latin motto)
Translation: "May faith grant light."

Motto of St. Gregory's College, Shawnee, Oklahoma, USA.

fiducial (adjective), more fiducial, most fiducial
1. Of or pertaining to, or of the nature of, trust or reliance.
2. Regarded or used as a standard of reference, as in surveying.
fiduciary (adjective), more fiduciary, most fiduciary
1. In trust of a person or thing; holding something in trust.
2. Of or pertaining to a trustee; pertaining to or of the nature of a trusteeship; held in trust.
3. Relating to or depending on confidence in a government for the value of fiat money (paper money decreed to be legal tender, not backed by gold or silver and not necessarily redeemable in coin).
In fide fiducia. (Latin motto)
Translation: "There is trust in faith."

Motto of Leys School, Cambridge, U.K.

In fide vestra virtutem in virtute autem scientiam. (Latin motto)
Translation: "[Have] virtue in your faith but knowledge in your virtue."

Motto of Agnes Scott College, Decatur, Georgia, USA.

In fide, justitia, et fortitudine.
In faith, justice, and strength.

Motto of the Order of St. George, Bavaria, Germany.

infidel (s) (noun), infidels (pl)
1. Anyone who does not believe in what the speaker or writer holds to be the true religion; an unbeliever; applied especially to Christianity or Islam.
2. A disbeliever in religion or divine revelation generally; especially one in a Christian country who professedly rejects or denies the divine origin and authority of Christianity; a professed unbeliever.
3. In Muslim use: a person who does not accept the Islamic faith; kaffir. Heard more often in the news as spoken by Muslims and applied even to Christians.
4. A person who has no religious beliefs; an unbeliever.
5. Loosely, anyone who disbelieves or doubts a particular theory, belief, creed, etc.; a skeptic.

Trust in Allah, but tie your camel.

—Arabian proverb

infidel: In New York, one who does not believe in the Christian religion; in Constantinople, one who does.

—Ambrose Bierce (1842-1914), The Devil's Dictionary, 1906.
infidelity (s) (noun), infidelities (pl)
Disloyalty to a person; such as, to a sovereign, lord, master, friend, lover: "In modern use, infidelity to a husband or wife is sometimes called conjugal infidelity."

Eighty percent of married men cheat in America. The rest cheat in Europe.

—Jackie Mason, American comedian

Heav'n has no rage, like love to hatred turn'd,

Nor Hell a fury like a woman scorn’d.

—William Congreve
libertas et fidelitate
Freedom and loyalty.

Motto on the seal of the State of West Virginaia, USA.

Lux et fides.
Light and faith.

Motto of Taylor University, Upland, Indiana, USA.

Cross references of word families that are related directly, or indirectly, to: "faith, trust; faithful, trusting; believe, belief": cred-; dox-.