Faith is complete trust or confidence in someone or something.
In religious context, faith refers to strong belief in God or in the doctrines of a religion, based on spiritual apprehension rather than proof.
The term "faith" can also mean:
1. A system of religious belief (e.g. the Christian faith)
2. Loyalty or allegiance to a person or thing
3. A promise or assurance (keep faith with someone)
4. In expressions like "good faith" or "bad faith"