# faithful

Pronunciation: say "FAYTH-fuhl" /ˈfeɪθ.fl̩/

## Adjective

1. Loyal and firmly devoted to a person or a cause.
   - Simple: Staying loyal to a person or to a cause you believe in.
   - _He remained faithful to the union through three long strikes._
   - _The senator thanked her faithful supporters, many of whom had campaigned for her since her first race._
2. Having sexual relations only with one's spouse or long-term partner.
   - Simple: Having sex only with your husband, wife, or long-term partner.
   - _Staying faithful through two years of a long-distance relationship took real commitment._
   - _He insisted he had always been faithful to his wife, but the messages on his phone told a different story._
3. Accurately reflecting reality or the real thing being described or copied.
   - Simple: True to the facts or very close to the real thing.
   - _The museum built a faithful replica of the ship, down to the hand-carved figurehead._
   - _Critics praised the translation as faithful to the original without sounding stiff._
4. Dependable and deserving of trust.
   - Simple: Able to be trusted and counted on.
   - _The faithful old furnace kept the farmhouse warm through another hard winter._
   - _For forty years she was a faithful correspondent, answering every letter within a week._
6. Having faith, especially firm religious belief.
   - Simple: Believing strongly, especially in God or a religion.
   - _Faithful Catholics were urged to attend Mass on the holy day._
   - _Though he became a scientist, he stayed faithful all his life and saw no conflict between prayer and research._
8. Injective in a specific setting, as said of a representation in representation theory or a functor in category theory.
   - Simple: In math, describes a map that keeps different things different, used of certain representations and functors.
   - _The regular representation of any finite group is faithful._
   - _The forgetful functor from groups to sets is faithful but not full._
9. Of a module over a ring: having zero annihilator, so that no nonzero ring element sends every element of the module to zero.
   - Simple: In algebra, describes a module that only the zero of the ring can turn completely into zero.
   - _Because 6 annihilates every element of Z/6Z, that module is not faithful over the integers._
   - _Every nonzero torsion-free abelian group is faithful as a module over the integers._

## Noun

5. The people who practice a religion or follow a cause, considered as a group.
   - Simple: All the people who follow a religion or support a cause.
   - _Thousands of the faithful gathered in the square for the Easter blessing._
   - _The candidate saved his fiercest lines for the party faithful in the front rows._
7. A loyal or reliable person or thing, one that can always be counted on.
   - Simple: A person or thing you can always count on.
   - _When someone in the house gets sick, chicken soup is the old faithful we turn to._
   - _The restaurant changed its menu but kept the old faithfuls that regulars order every week._

## Origin

From Middle English feithful, equivalent to faith + -ful.

Source: DictionaryAI, https://dictionaryai.com/define/faithful (written from Wiktionary data, CC BY-SA 4.0: https://creativecommons.org/licenses/by-sa/4.0/).