| Term | Definition |
| fid | faith, trust |
| affidavit | sworn written statement made before an authorized official |
| bona fide | made or carried out in good faith; genuine |
| confidant | (confidante, if a woman) one to whom secrets are entrusted |
| confident | having faith in oneself; self-reliant; sure |
| confidential | comjunicated in trust; secret; private |
| deffident | lacking faith in oneself; timid; shy |
| fidelity | faithfulness to a trust or vow, accuracy,as a recording |
| fiduciary | held in trust; confidential |
| infidel | one who does not accept a particular faith; unbeliever |
| perfidious | false to a trust; faithless |
| perfidy | violation of a trust; treachery; faithlessness. |