---
title: "BIP39 Word #664: fancy — Seed Phrase Mnemonic Word"
url: "https://bip39-phrase.com/bip39-word/fancy/"
language: "en"
updated: "2026-10-19T00:00:00+00:00"
---

Word #664 01010010111 

# fancy — BIP39 word #664

"**fancy**" is word #664 of the 2048 words in the official BIP39 English wordlist, between [fan](/bip39-word/fan/) and [fantasy](/bip39-word/fantasy/). In a seed phrase it stands for the 11-bit value `01010010111`, decimal index 663\. 

/ˈfænsi/  · _adjective:_ elaborate and highly decorated, or expensive and stylish 

[Russian](/ru/ "The BIP39 wordlist with Russian translations"): причудливый 

## Binary Representation

Six 1-bits and five 0-bits; 462 of the 2048 indexes have exactly six 1-bits.

One wrong bit turns it into (leftmost bit first):

[spray](/bip39-word/spray/)[base](/bip39-word/base/)[indicate](/bip39-word/indicate/)[drill](/bip39-word/drill/)[foot](/bip39-word/foot/)[finger](/bip39-word/finger/)[extend](/bip39-word/extend/)[fault](/bip39-word/fault/)[fame](/bip39-word/fame/)[famous](/bip39-word/famous/)[fan](/bip39-word/fan/) 

Position

Hex Index

0x297

4-Letter Prefix

fanc

## About "fancy" in BIP39

- "fancy" has 5 letters, but the first four, **"fanc"**, already identify it, because **"fan"** also begins [fan](/bip39-word/fan/) and [fantasy](/bip39-word/fantasy/).
- Its first letters also spell another BIP39 word, [fan](/bip39-word/fan/). Write "fancy" out in full: cut short, it turns into a different valid word.
- "fancy" appears in one of the 24 official English [test vectors](https://github.com/trezor/python-mnemonic/blob/master/vectors.json) of BIP39: vector #15 (word 14 of 24). Every official vector passes the [checksum checker](/bip39-checksum-checker/), and [How BIP39 works](/how-bip39-works/) shows how the entropy turns into such words.

Official test vector #15

[hamster](/bip39-word/hamster/) [diagram](/bip39-word/diagram/) [private](/bip39-word/private/) [dutch](/bip39-word/dutch/) [cause](/bip39-word/cause/) [delay](/bip39-word/delay/) [private](/bip39-word/private/) [meat](/bip39-word/meat/) [slide](/bip39-word/slide/) [toddler](/bip39-word/toddler/) [razor](/bip39-word/razor/) [book](/bip39-word/book/) [happy](/bip39-word/happy/) fancy [gospel](/bip39-word/gospel/) [tennis](/bip39-word/tennis/) [maple](/bip39-word/maple/) [dilemma](/bip39-word/dilemma/) [loan](/bip39-word/loan/) [word](/bip39-word/word/) [shrug](/bip39-word/shrug/) [inflict](/bip39-word/inflict/) [delay](/bip39-word/delay/) [length](/bip39-word/length/) 

## Word #664 in the Other 9 BIP39 Wordlists

[Czech](/czech/) koza 

[French](/french/) enclave 

[Italian](/italian/) flacone 

[Japanese](/japanese/) このよ 

[Korean](/korean/) 복도 

[Portuguese](/portuguese/) edital 

[Spanish](/spanish/) exilio 

[Traditional Chinese](/chinese-traditional/) 帝 

[Simplified Chinese](/chinese-simplified/) 帝 

## Similar Words — Check Carefully During Recovery

Words sharing the first three letters "fan":

[fan](/bip39-word/fan/)[fantasy](/bip39-word/fantasy/) 

## More BIP39 Words Starting with "F"

[ #660 fame ](/bip39-word/fame/)[ #661 family ](/bip39-word/family/)[ #662 famous ](/bip39-word/famous/)[ #663 fan ](/bip39-word/fan/)[ #665 fantasy ](/bip39-word/fantasy/)[ #666 farm ](/bip39-word/farm/)[ #667 fashion ](/bip39-word/fashion/)[ #668 fat ](/bip39-word/fat/) 

[View all words starting with "F" ](/bip39-words/f/) 

## Seed phrase, key and recovery guides

- [EVM Address Format Explained: Structure & Usage](/format-evm-addresses/)
- [Is a Seed Phrase Case Sensitive? BIP39 Words vs Passphrase](/is-seed-phrase-case-sensitivity-really-important/)
- [BIP-444 (Now BIP 110): Reduced Data Temporary Softfork Explained](/bip-444-reduced-data-temporary-softfork/)

[ Full BIP39 Wordlist ](/)