Exact Match:
- dead letter
- mail that can neither be delivered nor returned
- the state of something that has outlived its relevance
Synonyms:
- Pastoral Epistle,
- aerogram,
- aimlessness,
- air letter,
- airgraph,
- billet-doux,
- bull,
- chain letter,
- dimissorial,
- dimissory letter,
- drop letter,
- emptiness,
- empty sound,
- encyclical,
- fan letter,
- form letter,
- futility,
- inanity,
- insignificance,
- letter of credit,
- letter of introduction,
- letters credential,
- letters of marque,
- letters of request,
- letters overt,
- letters patent,
- letters rogatory,
- love letter,
- meaninglessness,
- mere noise,
- monitory,
- newsletter,
- nixie,
- noise,
- nonsensicality,
- nullity,
- open letter,
- pastoral letter,
- phatic communion,
- poison-pen letter,
- purposelessness,
- round robin,
- senselessness,
- unmeaningness,
- unsignificancy