再见

goodbye; bye; see you later; farewell; ciao; cheers; adieu; cheerio; ta-ta; see you; see you again; later; sayonara; au revoir; so long; TTFN (short for ta-ta for now); BFN (short for bye for now)

永远

forever; always; ever; eternally; perpetually; permanently; evermore; eternal; timeless; everlasting; undying; perpetual; immortal; ageless; for good; for keeps; in perpetuity; for all time; from everlasting to everlasting; eternity; perpetuity

不见

disappear; be missing; be lost; vanish; be gone; be unseen